2019年8月8日开始编写，等50题做完了希望不会太晚。
本篇纯属本人的练手作业，本人也不是什么大神，仅供参考。
题目1
package SU;
/**
* @ClassName WayRabbit
* @Description 有一对兔子，从出生后第3个月起每个月都生一对兔子，小兔子长到第三个月后每个月又生一对兔子，假如兔子都不死，问每个月的兔子总数为多少？
* @Author TumTam
* @Date 2019/8/8 14:12
* @Version 1.0
**/
public class WayRabbit {
public int WayRabbit(int m){
if(m==1|m==2){
return 1;
}else{
return WayRabbit(m-1)+WayRabbit(m-2);
}
}
}
package SU;
import java.util.Scanner;
public class WayRabbitTest {
public static void main(String[] args) {
System.out.println("你想知道第几个月的兔子数？");
Scanner months =new Scanner(System.in);
int m = months.nextInt();
months.close();
WayRabbit wr =new WayRabbit();
int num = wr.WayRabbit(m);
System.out.println("第"+m+"个月的兔子有："+num+"对");
}
}
题目2
package SU;
/**
* @ClassName IsPrime
* @Description 判断101-200之间有多少个素数，并输出所有素数。
* @Author TumTam
* @Date 2019/8/8 14:58
* @Version 1.0
**/
public class IsPrime {
//修改为指定范围内的素数
public IsPrime(int min,int max){
int count =0;
int n=min;
int m=max;
for(;n
Boolean b =true;
for(int i=2;i<n;i++){
if(n%i==0){
b =false;
break;
}
}
if(b==true){
count++;
System.out.print(n+" ");
}
}
System.out.println();
System.out.println("在"+min+"和"+max+"范围内共有"+count+"个素数。");
}
}
package SU;
import java.util.Scanner;
public class IsPrimeTest {
public static void main(String[] args) {
System.out.println("输入最大值、最小值确认范围来输出其中的素数：");
Scanner num =new Scanner(System.in);
int a=num.nextInt();
int b=num.nextInt();
num.close();
int max;
int min;
if(a>b){
max = a;
min = b;
}else{
max = b;
min = a;
}
IsPrime ip =new IsPrime(min,max);
}
}
题目3
package SU;
/**
* @ClassName NarcissisticNumber
* @Description 打印出所有的"水仙花数"，所谓"水仙花数"是指一个三位数，其各位数字立方和等于该数本身。
* @Author TumTam
* @Date 2019/8/8 15:32
* @Version 1.0
**/
public class NarcissisticNumber {
//修改为指定范围的水仙花数
public NarcissisticNumber(int min,int max){
int n = min;
int m = max;
int count =0;
for(;n
int hundred = n /100;
int decade = n /10%10;
int unit = n %10;
int total = hundred * hundred * hundred + decade * decade * decade + unit * unit * unit;
if(n==total){
count++;
System.out.print(n+" ");
}
}
System.out.println("在"+min+"和"+max+"范围内共有"+count+"个水仙花数");
}
}
package SU;
import java.util.Scanner;
public class NarcissisticNumberTest {
public static void main(String[] args) {
System.out.println("输入最大值、最小值确认范围来输出其中的水仙花数(三位数)：");
Scanner num =new Scanner(System.in);
int a=num.nextInt();
int b=num.nextInt();
num.close();
int max;
int min;
if(a>b){
max = a;
min = b;
}else{
max = b;
min = a;
}
NarcissisticNumber nn =new NarcissisticNumber(min,max);
}
}
题目4
package SU;
/**
* @ClassName Factorization
* @Description 将一个正整数分解质因数。例如：输入90,打印出90=2*3*3*5
* @Author TumTam
* @Date 2019/8/8 15:55
* @Version 1.0
**/
public class Factorization {
public Factorization(int num){
System.out.print(num+"=");
int current = num;
for(int i=2;i
if(current%i==0){
System.out.print(i+"*");
current=current/i;
i=1;
}
}
System.out.print(current);
}
}
package SU;
import java.util.Scanner;
public class FactorizationTest {
public static void main(String[] args) {
System.out.println("你想因式分解哪个因数？");
Scanner num =new Scanner(System.in);
int n = num.nextInt();
num.close();
Factorization f =new Factorization(n);
}
}
题目5
package SU;
/**
* @ClassName ConditionalOperator
* @Description 利用条件运算符的嵌套来完成此题：学习成绩>=90分的同学用A表示，60-89分之间的用B表示，60分以下的用C表示。
* @Author TumTam
* @Date 2019/8/8 16:12
* @Version 1.0
**/
public class ConditionalOperator {
public ConditionalOperator(int score){
String Grade = (score>=90) ?"A" :((score>=60)?"B" :"C");
System.out.println("当前分数所属等级为："+Grade);
}
}
package SU;
import java.util.Scanner;
public class ConditionalOperatorTest {
public static void main(String[] args) {
System.out.println("输入你的分数：");
Scanner score =new Scanner(System.in);
int s = score.nextInt();
score.close();
ConditionalOperator co =new ConditionalOperator(s);
}
}
题目6
package SU;
/**
* @ClassName GreatestCommonDivisorAndLeastCommonMultiple
* @Description 输入两个正整数m和n，求其最大公约数和最小公倍数。
* @Author TumTam
* @Date 2019/8/8 16:24
* @Version 1.0
**/
public class GreatestCommonDivisorAndLeastCommonMultiple {
public GreatestCommonDivisorAndLeastCommonMultiple(int a,int b){
int GreatestCommonDivisor=1;
int LeastCommonMultiple;
int max = Max(a,b);
for(int i=1;i<max;i++){
if(a%i==0 && b%i==0){
GreatestCommonDivisor=Max(GreatestCommonDivisor,i);
}
}
LeastCommonMultiple = (a*b)/GreatestCommonDivisor;
System.out.println(a+"和"+b+"的最大公约数为："+GreatestCommonDivisor);
System.out.println(a+"和"+b+"的最小公倍数为："+LeastCommonMultiple);
}
public int Max(int x,int y){
if(x>y){
return x;
}else{
return y;
}
}
}
package SU;
import java.util.Scanner;
public class GreatestCommonDivisorAndLeastCommonMultipleTest {
public static void main(String[] args) {
System.out.println("输入两个数求他们的最大公因数和最小公倍数。");
Scanner Num =new Scanner(System.in);
int m = Num.nextInt();
int n = Num.nextInt();
Num.close();
GreatestCommonDivisorAndLeastCommonMultiple gcdANDlcm =new GreatestCommonDivisorAndLeastCommonMultiple(m,n);
}
}
题目7
package SU;
/**
* @ClassName Statistics
* @Description 输入一行字符，分别统计出其英文字母、空格、数字和其它字符的个数。
* @Author TumTam
* @Date 2019/8/9 8:25
* @Version 1.0
**/
public class Statistics {
int chara =0,blank=0,number=0,others=0;
public Statistics(String s){
for(int i=0;i
char c = s.charAt(i);
if(c>='a'&&c<='z'){
chara++;
}else if(c>'A'&&c<'Z'){
chara++;
}else if(c==' '){
blank++;
}else if(c>='0'&&c<='9'){
number++;
}else{
others++;
}
}
System.out.println("当前字符串里共有：");
System.out.println("英文字母有"+chara+"个。");
System.out.println("空格有"+blank+"个。");
System.out.println("数字有"+number+"个。");
System.out.println("其他字符有"+others+"个。");
}
}
package SU;
import java.util.Scanner;
public class StatisticsTest {
public static void main(String[] args) {
System.out.println("请输入一串字符：");
Scanner sentence =new Scanner(System.in);
String s = sentence.nextLine();
sentence.close();
Statistics st =new Statistics(s);
}
}
题目8
package SU;
/**
* @ClassName Sum
* @Description 求s=a+aa+aaa+aaaa+aa...a的值，其中a是一个数字。例如2+22+222+2222+22222(此时共有5个数相加)，几个数相加有键盘控制。输出结果的形式如：2+22+222=246；
* @Author TumTam
* @Date 2019/8/9 10:36
* @Version 1.0
**/
public class Sum {
//更改为输入的数字可以是任意数，可以输入重复次数，例如：
//请输入要使用的一个数：
//12
//请输入要使用的次数：
//3
//12+1212+121212=122436
public Sum(int num,int times){
int sum=0;
StringBuffer sb =new StringBuffer();
for(int i=0;i
sb.append(num);
String s = sb.toString();
int a=Integer.parseInt(s);
sum+=a;
System.out.print(a);
if(i<(times-1)){
System.out.print("+");
}else{
System.out.print("=");
System.out.print(sum);
}
}
}
}
package SU;
import java.util.Scanner;
public class SumTest {
public static void main(String[] args) {
Scanner ctr =new Scanner(System.in);
System.out.println("请输入要使用的一个数：");
int num = ctr.nextInt();
System.out.println("请输入要使用的次数：");
int times = ctr.nextInt();
ctr.close();
Sum sum =new Sum(num,times);
}
}
题目9
package SU;
/**
* @ClassName PerfectNumber
* @Description 一个数如果恰好等于它的因子之和，这个数就称为"完数"。例如6=1＋2＋3.编程找出1000以内的所有完数。
* @Author TumTam
* @Date 2019/8/9 11:10
* @Version 1.0
**/
public class PerfectNumber {
public PerfectNumber(int min, int max){
int n=min;
int m=max;
for(;n<m;n++){
int current = n;
int sum=1;
int i=2;
for(;i<=current;i++){
if(current%i==0){
sum+=i;
current=current/i;
i=1;
}
}
if(n==sum){
System.out.print(n+" ");
}
}
}
}
package SU;
import java.util.Scanner;
public class PerfectNumberTest {
public static void main(String[] args) {
System.out.println("输入最大值、最小值确认范围来输出其中的完数：");
Scanner num =new Scanner(System.in);
int a=num.nextInt();
int b=num.nextInt();
num.close();
int max;
int min;
if(a>b){
max = a;
min = b;
}else{
max = b;
min = a;
}
PerfectNumber pn =new PerfectNumber(min,max);
}
}
题目10
package SU;
/**
* @ClassName BallWay
* @Description 一球从h米高度自由落下，每次落地后反跳回原高度的一半；
* 再落下，求它在 第n次落地时，共经过多少米？第n次反弹多高？
* @Author TumTam
* @Date 2019/8/9 12:51
* @Version 1.0
**/
public class BallWay {
double height=0;
double way=0;
public double Height(double h,int n) {
if (n ==1) {
return h/2;
}else if(n==0){
return 0;
}else{
height=h/2;
h=height;
n--;
return Height(h,n);
}
}
public double Way(double h,int n){
int num = n-1;
way=way+h;
//i从1开始，去除第一次落地的情况，第一次落地不用乘2，放在了上行。
for(int i=1;i
way+=Height(h,num)*2;
num--;
}
return way;
}
}
package SU;
import java.util.Scanner;
public class BallWayTest {
public static void main(String[] args) {
Scanner base =new Scanner(System.in);
System.out.println("请输入初始高度：");
double h = base.nextDouble();
System.out.println("请输入次数：");
int n = base.nextInt();
base.close();
BallWay bw =new BallWay();
double height = bw.Height(h,n);
double way = bw.Way(h,n);
System.out.println("第"+n+"次弹起的高度为"+height);
System.out.println("第"+n+"次落地经过的路程为"+way);
}
}
题目11
package SU;
/**
* @ClassName FormFigure
* @Description 有1、2、3、4个数字，能组成多少个互不相同且无重复数字的三位数？都是多少？
* @Author TumTam
* @Date 2019/8/9 14:50
* @Version 1.0
**/
public class FormFigure {
public FormFigure(){
int sum =0;
for(int i=1;i<=4;i++){
for(int j=1;j<=4;j++){
for(int k=1;k<=4;k++){
if(i!=j && j!=k && k!=i){
int a=i*100+j*10+k;
System.out.print(a+" ");
sum++;
if(sum%6==0){
System.out.println();
}
}
}
}
}
System.out.println("共有"+sum+"个符合条件的三位数。" );
}
}
package SU;
public class FormFigureTest {
public static void main(String[] args) {
FormFigure ff =new FormFigure();
}
}
题目12
package SU;
import java.math.BigDecimal;
/**
* @ClassName Bonus
* @Description 企业发放的奖金根据利润提成。
* 利润(I)低于或等于10万元时，奖金可提10%；
* 利润高于10万元，低于20万元时，低于10万元的部分按10%提成，高于10万元的部分，可可提成7.5%；
* 20万到40万之间时，高于20万元的部分，可提成5%；
* 40万到60万之间时高于40万元的部分，可提成3%；
* 60万到100万之间时，高于60万元的部分，可提成1.5%，高于100万元时，超过100万元的部分按1%提成，
* 从键盘输入当月利润I，求应发放奖金总数？
* @Author TumTam
* @Date 2019/8/9 15:08
* @Version 1.0
**/
public class Bonus {
int key1 =1000000;
int key2 =600000;
int key3 =400000;
int key4 =200000;
int key5 =100000;
BigDecimalpercent =new BigDecimal(Integer.toString(0));
BigDecimaldeal =new BigDecimal(Integer.toString(0));
BigDecimaltemp =new BigDecimal(Integer.toString(0));
BigDecimalbonus =new BigDecimal(Integer.toString(0));
public BigDecimalBonus(double I){
int d =(int) I/key5;
switch (d){
default:
case 10:
{
percent =new BigDecimal(Double.toString(0.01));
deal =new BigDecimal(Double.toString(I -key1));
temp =percent.multiply(deal);
bonus =bonus.add(temp);
}
case 9:
case 8:
case 7:
case 6:
{
percent =new BigDecimal(Double.toString(0.015));
if (I >key1) {
deal =new BigDecimal(Integer.toString(key1 -key2));
}else {
deal =new BigDecimal(Double.toString(I -key2));
}
temp =percent.multiply(deal);
bonus =bonus.add(temp);
}
case 5:
case 4:
{
percent =new BigDecimal(Double.toString(0.03));
if (I >key2) {
deal =new BigDecimal(Integer.toString(key2 -key3));
}else {
deal =new BigDecimal(Double.toString(I -key3));
}
temp =percent.multiply(deal);
bonus =bonus.add(temp);
}
case 3:
case 2:
{
percent =new BigDecimal(Double.toString(0.05));
if (I >key3) {
deal =new BigDecimal(Integer.toString(key3 -key4));
}else {
deal =new BigDecimal(Double.toString(I -key4));
}
temp =percent.multiply(deal);
bonus =bonus.add(temp);
}
case 1:
{
percent =new BigDecimal(Double.toString(0.075));
if (I >key4) {
deal =new BigDecimal(Integer.toString(key4 -key5));
}else {
deal =new BigDecimal(Double.toString(I -key5));
}
temp =percent.multiply(deal);
bonus =bonus.add(temp);
}
case 0:
{
percent =new BigDecimal(Double.toString(0.1));
if (I >key5) {
deal =new BigDecimal(Integer.toString(key5));
}else {
deal =new BigDecimal(Double.toString(I));
}
temp =percent.multiply(deal);
bonus =bonus.add(temp);
break;
}
}
return bonus;
}
}
package SU;
import java.math.BigDecimal;
import java.util.Scanner;
public class BonusTest {
public static void main(String[] args) {
Scanner ints =new Scanner(System.in);
System.out.println("请输入总利润来计算奖金；");
double I = ints.nextDouble();
ints.close();
Bonus b =new Bonus();
BigDecimal bd = b.Bonus(I);
System.out.println(I+"元共计可获得奖金"+bd+"元。");
}
}
题目13
package SU;
/**
* @ClassName Judge
* @Description 一个整数，它加上100后是一个完全平方数，再加上168又是一个完全平方数，请问该数是多少？
* @Author TumTam
* @Date 2019/8/9 16:40
* @Version 1.0
**/
public class Judge {
int count =0;
public Judge(int num){
int n = num+100;
int m = n+168;
boolean x = PerfectSquareNumber(n);
boolean y = PerfectSquareNumber(m);
if(x==true && y==true){
System.out.print(num+" ");
count ++;
if(count%10==0){
System.out.println();
}
}
}
public boolean PerfectSquareNumber(int num){
boolean b =false;
for(int i=0; i<=(num/2);i++){
int temp = i*i;
if(num==temp){
b=true;
break;
}
}
return b;
}
}
package SU;
import java.util.Scanner;
public class JudgeTest {
public static void main(String[] args) {
System.out.println("请输入想找出多少以内符合条件的数：");
Scanner max =new Scanner(System.in);
int m = max.nextInt();
max.close();
System.out.println("符合条件的数有;");
for(int i=0;i<=m;i++){
Judge j =new Judge(i);
}
}
}
题目14
package SU;
/**
* @ClassName YearJudgment
* @Description 输入某年某月某日，判断这一天是这一年的第几天？
* @Author TumTam
* @Date 2019/8/12 8:28
* @Version 1.0
**/
public class YearJudgment {
public YearJudgment(){}
public YearJudgment(int year,int month,int day){
int J= Judgment(year,month,day);
int total = day;
for(int i=0;i<(month-1);i++){
total+= Judgment(year,1,day);
}
System.out.println("这一天是这一年的第"+total+"天");
}
public int Judgment(int year,int month,int day){
int []array = {31,28,31,30,31,30,31,31,30,31,30,31};
if(month<=0|month>12){
return 0;
}else{
if(year%4==0 | year % (-4) ==0){
array[1]=29;
return array[month-1];
}else{
array[1]=28;
return array[month-1];
}
}
}
}
package SU;
import java.util.Scanner;
public class YearJudgmentTest {
public static void main(String[] args) {
Scanner YMD =new Scanner(System.in);
System.out.println("请输入年份：");
int year = YMD.nextInt();
System.out.println("请输入月份：");
int month = YMD.nextInt();
System.out.println("请输入具体日期：");
int day = YMD.nextInt();
YMD.close();
YearJudgment yj =new YearJudgment();
if(yj.Judgment(year,month,day) ==0 ){
System.out.println("你输入的月份有误！");
}else if(day>yj.Judgment(year,month,day)|day<1){
System.out.println("你输入的日期有误！");
}else{
YearJudgment YJ =new YearJudgment(year,month,day);
}
}
}
题目15
package SU;
/**
* @ClassName Compare
* @Description 输入三个整数x,y,z，请把这三个数由小到大输出。
* @Author TumTam
* @Date 2019/8/12 14:37
* @Version 1.0
**/
public class Compare {
public Compare(double a,double b,double c){
if(a>b){
if(a>c) {
if(b>c){
System.out.println(a+">"+b+">"+c);
}else{
System.out.println(a+">"+c+">"+b);
}
}else{
System.out.println(c+">"+a+">"+b);
}
}else{
if(a<c){
if(b<c){
System.out.println(c+">"+b+">"+a);
}else{
System.out.println(b+">"+c+">"+a);
}
}else{
System.out.println(b+">"+a+">"+c);
}
}
}
}
package SU;
import java.util.Scanner;
public class CompareTest {
public static void main(String[] args) {
Scanner number =new Scanner(System.in);
double x=0;
double y=0;
double z=0;
System.out.println("请输入三个数：");
if(number.hasNextDouble()){
x = number.nextDouble();
y = number.nextDouble();
z = number.nextDouble();
}else{
System.out.println("你输入的不是数字！");
}
number.close();
Compare c =new Compare(x,y,z);
}
}
程序16
package SU;
/**
* @ClassName multiplication
* @Description 输出9*9口诀。
* @Author TumTam
* @Date 2019/8/12 15:06
* @Version 1.0
**/
public class Multiplication {
public Multiplication(){
for(int i=1;i<=9;i++){
for(int j=1;j<=i;j++){
System.out.print(j+"*"+i+"="+(j*i)+" ");
if(i==j){
System.out.println();
}
}
}
}
}
package SU;
public class multiplicationTest {
public static void main(String[] args) {
Multiplication Mp =new Multiplication();
}
}
程序17
package SU;
/**
* @ClassName Monkey
* @Description 猴子吃桃问题：
* 猴子第一天摘下若干个桃子，当即吃了一半，还不瘾，又多吃了一个
* 第二天早上又将剩下的桃子吃掉一半，又多吃了一个。
* 以后每天早上都吃了前一天剩下的一半零一个。
* 到第10天早上想再吃时，见只剩下一个桃子了。求第一天共摘了多少。
* @Author TumTam
* @Date 2019/8/12 15:24
* @Version 1.0
**/
public class Monkey {
int peach =0;
public Monkey(){
for(int i=0;i<8;i++){
peach =(peach+1)*2;
}
System.out.println("第一天共摘了"+peach+"个桃子");
}
}
package SU;
public class MonkeyTest {
public static void main(String[] args) {
Monkey m =new Monkey();
}
}
程序18
package SU;
import java.util.Arrays;
import java.util.List;
/**
* @ClassName Competition
* @Description 两个乒乓球队进行比赛，各出三人。
* 甲队为a,b,c三人，乙队为x,y,z三人。
* 已抽签决定比赛名单。有人向队员打听比赛的名单。
* a说他不和x比，c说他不和x,z比，请编程序找出三队赛手的名单。
* @Author TumTam
* @Date 2019/8/12 15:36
* @Version 1.0
**/
public class Competition {
Stringa="a";
Stringb="b";
Stringc="c";
StringBuffersb =new StringBuffer();
StringBuffertemp =new StringBuffer();
Listlist1 = Arrays.asList("a","b","c");
Listlist2 = Arrays.asList("x","y","z");
int count =0;
public Competition(){
while(sb.indexOf(a)==-1 ||sb.indexOf(b)==-1 ||sb.indexOf(c) ==-1){
if(count>=9){
sb.setLength(0);
count=0;
int a = (int) (Math.random()*3);
String T =list1.get(a);
int b;
if(a+1>2){
b = a+1-2;
}else{
b=a+1;
}
list1.set(a,list1.get(b));
list1.set(b,T);
}
for(String s:list1){
for(String k:list2){
if(sb.indexOf(s)==-1 &&sb.indexOf(k)==-1){
temp.setLength(0);
temp.append(s);
temp.append(k);
String t =temp.toString();
if(!"ax".equals(t) && !"cx".equals(t) && !"cz".equals(t)){
sb.append(t);
sb.append(" ");
}
}
count++;
}
}
}
System.out.println(sb.toString());
}
}
package SU;
public class CompetitionTest {
public static void main(String[] args) {
System.out.println("三队赛手的名单：");
Competition c =new Competition();
}
}
题目19
package SU;
/**
* @ClassName PrintS
* @Description 打印出如下图案（菱形）
*
* *
* ***
* ******
* ********
* ******
* ***
* *
* @Author TumTam
* @Date 2019/8/13 8:28
* @Version 1.0
**/
public class PrintS {
int star =1;
public PrintS(){
for(int i=1;i<8;i++){
int a = Math.abs(i-4);
for(int j=0;j
System.out.print(" ");
}
for (int k=0;k
System.out.print("*");
}
System.out.println();
if(i<4){
star+=2;
}else {
star-=2;
}
}
}
}
package SU;
public class PrintSTest {
public static void main(String[] args) {
PrintS ps =new PrintS();
}
}
题目20
package SU;
/**
* @ClassName SumFraction
* @Description 有一分数序列：2/1，3/2，5/3，8/5，13/8，21/13... 求出这个数列的前20项之和。
* @Author TumTam
* @Date 2019/8/13 8:46
* @Version 1.0
**/
public class SumFraction {
int sum =0 ;
public SumFraction(int n){
int [] numerator =new int[n];
int [] denominator =new int[n];
numerator[0]=2;
numerator[1]=3;
denominator[0]=1;
denominator[1]=2;
for(int i=2;i
numerator[i] = numerator[i-1]+numerator[i-2];
denominator[i] = denominator[i-1]+denominator[i-2];
}
for(int j=0;j
sum+=(numerator[j]/denominator[j]);
}
System.out.println(sum);
}
}
package SU;
import java.util.Scanner;
public class SumFractionTest {
public static void main(String[] args) {
System.out.println("请输入想要求前几个数的和：");
Scanner fra =new Scanner(System.in);
int n = fra.nextInt();
fra.close();
SumFraction sf =new SumFraction(n);
}
}
题目21
package SU;
/**
* @ClassName Factorial
* @Description 求1+2!+3!+...+20!的和
* @Author TumTam
* @Date 2019/8/16 14:56
* @Version 1.0
**/
public class Factorial {
public int sum(int a){
int sum =0;
for(int i=1;i<=a;i++){
sum = sum +factorial(i);
}
return sum;
}
public int factorial(int a){
int result=1;
for(int i=1;i<=a;i++){
result = result*i;
}
return result;
}
}
package SU;
import java.util.Scanner;
public class FactorialTest {
public static void main(String[] args) {
System.out.println("你想求前多少位的阶乘之和？");
Scanner s =new Scanner(System.in);
int q = s.nextInt();
s.close();
Factorial f =new Factorial();
int sum = f.sum(q);
System.out.println("前"+q+"位的阶乘之和为"+sum);
}
}
题目22
package SU;
/**
* @ClassName RecursionFactorial
* @Description 利用递归方法求5!
* @Author TumTam
* @Date 2019/8/16 15:11
* @Version 1.0
**/
public class RecursionFactorial {
int c =1;
public int count(int a){
if(a==1){
return c;
}else {
return a*count(a-1);
}
}
}
package SU;
import java.util.Scanner;
public class RecursionFactorialTest {
public static void main(String[] args) {
System.out.println("你想求谁的阶乘？");
Scanner sr =new Scanner(System.in);
int v = sr.nextInt();
sr.close();
RecursionFactorial rf =new RecursionFactorial();
int s = rf.count(v);
System.out.println(v+"的阶乘为"+s);
}
}
题目23
package SU;
/**
* @ClassName RecursionProblem
* @Description 有5个人坐在一起，问第五个人多少岁？
* 他说比第4个人大2岁。问第4个人岁数，他说比第3个人大2岁。
* 问第三个人，又说比第2人大两岁。问第2个人，说比第一个人大两岁。
* 最后问第一个人，他说是10岁。请问第五个人多大？
* @Author TumTam
* @Date 2019/8/16 15:31
* @Version 1.0
**/
public class RecursionProblem {
public int RecursionProblem(int a,int b){
if(a==1){
return 10;
}else{
return RecursionProblem(a-1,b)+b;
}
}
}
package SU;
public class RecursionProblemTest {
public static void main(String[] args) {
RecursionProblem rp =new RecursionProblem();
int a = rp.RecursionProblem(5,2);
System.out.println("第五个人"+a+"岁");
}
}
题目24
package SU;
import java.util.ArrayList;
import java.util.List;
/**
* @ClassName PositiveInteger
* @Description 给一个不多于5位的正整数，
* 要求：一、求它是几位数，二、逆序打印出各位数字。
* @Author TumTam
* @Date 2019/8/16 15:49
* @Version 1.0
**/
public class PositiveInteger {
public PositiveInteger(int a){
int gw = a%10;
int sw = (a/10)%10;
int bw = (a/100)%10;
int qw = (a/1000)%10;
int ww = (a/10000)%10;
List list =new ArrayList<>(16);
if(ww !=0){
list.add(gw);
}
if(qw !=0){
list.add(sw);
}
if(bw !=0){
list.add(bw);
}
if(sw !=0){
list.add(qw);
}
if(gw !=0){
list.add(ww);
}
int length = list.size();
System.out.println("该数字为"+length+"位数。");
System.out.println("逆序输出结果为：");
for(Integer l : list){
System.out.print(l);
}
}
}
package SU;
import java.util.Scanner;
public class PositiveIntegerTest {
public static void main(String[] args) {
System.out.println("请输入一个5位以内的数字：");
Scanner sc =new Scanner(System.in);
int shu = sc.nextInt();
sc.close();
PositiveInteger pi =new PositiveInteger(shu);
}
}
题目25
package SU;
import java.util.ArrayList;
import java.util.List;
/**
* @ClassName PoInteger
* @Description 一个5位数，判断它是不是回文数。
* 即12321是回文数，个位与万位相同，十位与千位相同。
* @Author TumTam
* @Date 2019/8/19 11:23
* @Version 1.0
**/
public class PoInteger {
public PoInteger(int a){
int gw = a%10;
int sw = (a/10)%10;
int bw = (a/100)%10;
int qw = (a/1000)%10;
int ww = (a/10000)%10;
List list =new ArrayList<>(16);
if(ww !=0){
list.add(gw);
}
if(qw !=0){
list.add(sw);
}
if(bw !=0){
list.add(bw);
}
if(sw !=0){
list.add(qw);
}
if(gw !=0){
list.add(ww);
}
int x= list.size()/2+1;
int count =0;
for(int i =0; i
int j = list.size()-1-i;
if(list.get(i).equals(list.get(j))){
count ++;
}
}
if(count ==3){
System.out.println("这是一个回文数。");
}else {
System.out.println("这不是一个回文数。");
}
}
}
package SU;
import java.util.Scanner;
public class PoIntegerTest {
public static void main(String[] args) {
System.out.println("请输入一个5位数：");
Scanner sc =new Scanner(System.in);
int a = sc.nextInt();
sc.close();
PoInteger pi =new PoInteger(a);
}
}
题目26
package SU;
/**
* @ClassName WeekJug
* @Description 请输入星期几的第一个字母来判断一下是星期几，
* 如果第一个字母一样，则继续判断第二个字母。
* @Author TumTam
* @Date 2019/8/19 12:57
* @Version 1.0
**/
public class WeekJug {
public StringFirWeekJug(String s){
StringD="";
switch (s){
case "m":
D ="Monday";
break;
case "w":
D ="Wednesday";
break;
case "f":
D ="Friday";
break;
case "t":
D ="1";
break;
case "s":
D ="2";
break;
}
return D;
}
public StringSceWeekJug(String s){
StringD="";
switch (s) {
case "u":
D ="Tuesday";
break;
case "h":
D ="Thursday";
break;
}
return D;
}
public StringThrWeekJug(String s){
StringD="";
switch (s) {
case "a":
D ="Saturday";
break;
case "u":
D ="Sunday";
break;
}
return D;
}
}
package SU;
import java.util.Scanner;
public class WeekJugTest {
public static void main(String[] args) {
System.out.println("请输入第一个字母：");
Scanner sr =new Scanner(System.in);
String s = sr.next();
WeekJug wj =new WeekJug();
String sc = wj.FirWeekJug(s);
if("1"==sc ||"2"==sc){
System.out.println("请输入第二个字母：");
s = sr.next();
sr.close();
if("1"==sc){
sc = wj.SceWeekJug(s);
System.out.println(sc);
}else{
sc = wj.ThrWeekJug(s);
System.out.println(sc);
}
}else{
System.out.println(sc);
}
sr.close();
}
}
题目27
package SU;
/**
* @ClassName PrimeNumber
* @Description 求100之内的素数
* @Author TumTam
* @Date 2019/8/19 13:44
* @Version 1.0
**/
public class PrimeNumber {
public PrimeNumber(int a){
int count=0;
for(int i=3;i<=a;i++){
boolean b =true;
for(int j =2;j<=(i-1);j++){
if((i%j)==0){
b =false;
break;
}
}
if(true == b){
System.out.print(i+" ");
count++;
if(count%20==0){
System.out.println();
}
}
}
}
}
package SU;
import java.util.Scanner;
public class PrimeNumberTest {
public static void main(String[] args) {
System.out.println("你想求多少以内的素数：");
Scanner sc =new Scanner(System.in);
int a = sc.nextInt();
System.out.println(a+"之内的素数有：");
System.out.print("1"+" ");
PrimeNumber pn =new PrimeNumber(a);
}
}
题目28
package SU;
/**
* @ClassName DeSort
* @Description 对10个数进行排序
* @Author TumTam
* @Date 2019/8/19 14:23
* @Version 1.0
**/
public class DeSort {
public DeSort(int []a){
for(int w=0;w<a.length-1;w++)
{
for(int v=0;v<=a.length-w-2;v++)
{
int m=0;
if(a[v]>a[v+1])
{
m=a[v];
a[v]=a[v+1];
a[v+1]=m;
}
}
}
for(int f=0;f<a.length;f++)
{
System.out.print(a[f]+" ");
}
}
}
package SU;
import java.util.Scanner;
public class DeSortTest {
public static void main(String[] args) {
System.out.println("你想输入几个数？");
Scanner t =new Scanner(System.in);
int r=t.nextInt();
int a[]=new int[r];
System.out.println("请输入：");
Scanner n =new Scanner(System.in);
for(int f=0;f<r;f++)
{
a[f]=n.nextInt();
}
DeSort ds =new DeSort(a);
}
}
题目29
package SU;
/**
* @ClassName Matrix
* @Description 求一个3*3矩阵对角线元素之和
* @Author TumTam
* @Date 2019/8/19 14:33
* @Version 1.0
**/
public class Matrix {
public Matrix(int [][]a){
int s1 = a[0][0] + a[1][1] + a[2][2];
int s2 = a[0][2] + a[1][1] + a[2][0];
System.out.println("第一条对角线的值为："+s1);
System.out.println("第二条对角线的值为："+s2);
}
}
package SU;
import java.util.Scanner;
public class MatrixTest {
public static void main(String[] args) {
System.out.println("请输入9个数字：");
Scanner sc =new Scanner(System.in);
int [][]a =new int[3][3];
for(int i=0;i<3;i++){
for(int j=0;j<3;j++){
a[i][j]=sc.nextInt();
}
}
sc.close();
Matrix m =new Matrix(a);
}
}
题目30
package SU;
import org.apache.commons.lang3.ArrayUtils;
/**
* @ClassName InsertA
* @Description 有一个已经排好序的数组。
* 现输入一个数，要求按原来的规律将它插入数组中。
* @Author TumTam
* @Date 2019/8/19 15:00
* @Version 1.0
**/
public class InsertA {
public InsertA(int a){
int []y = {1,5,9,26,33,65,98,103,235,468,705,987,2065};
System.out.println("插入数前的数组为：");
for(int s:y){
System.out.print(s+" ");
}
int []x =new int[0];
for(int i=0;(i+1)
if(y[i]<a && a<=y[i+1]){
x=ArrayUtils.add(x,y[i]);
x=ArrayUtils.add(x,a);
}else{
x=ArrayUtils.add(x,y[i]);
}
}
x=ArrayUtils.add(x,y[y.length-1]);
System.out.println();
System.out.println("插入数字后的数组为：");
for(int s:x){
System.out.print(s+" ");
}
}
}
package SU;
import java.util.Scanner;
public class InsertATest {
public static void main(String[] args) {
System.out.println("请输入一个数：");
Scanner sc =new Scanner(System.in);
int a = sc.nextInt();
InsertA ia =new InsertA(a);
}
}
题目31
package SU;
/**
* @ClassName ReverseOrder
* @Description 将一个数组逆序输出。
* @Author TumTam
* @Date 2019/8/19 15:35
* @Version 1.0
**/
public class ReverseOrder {
public ReverseOrder(int []a){
// int []b = new int[a.length];
// for(int i=0;i<a.length;i++){
// b[i]=a[a.length-1-i];
// }
//
// for(int x:b){
// System.out.print(x+" ");
// }
for(int i=0;i<a.length;i++){
System.out.print(a[a.length-1-i]+" ");
}
}
}
package SU;
import java.util.Scanner;
public class ReverseOrderTest {
public static void main(String[] args) {
System.out.println("你想输入几个数？");
Scanner t =new Scanner(System.in);
int r=t.nextInt();
int a[]=new int[r];
System.out.println("请输入：");
for(int f=0;f
{
a[f]=t.nextInt();
}
t.close();
System.out.println("倒序输出：");
ReverseOrder ro =new ReverseOrder(a);
}
}
题目32
package SU;
/**
* @ClassName GetValue
* @Description TODO
* @Author TumTam
* @Date 2019/8/21 8:34
* @Version 1.0
**/
public class GetValue {
public GetValue(String sum){
StringBuffer sb =new StringBuffer();
String temp;
int result;
sb.append(sum);
temp = sb.reverse().toString().substring(4,8);
sb.setLength(0);
sb.append(temp);
temp =null;
temp = sb.reverse().toString();
result = Integer.parseInt(temp);
System.out.println("你输入数字从右开始的4到7位为:"+result);
}
}
package SU;
import java.util.Scanner;
public class GetValueTest {
public static void main(String[] args) {
System.out.println("请输入一个7位以上的数字：");
Scanner sd =new Scanner(System.in);
String num = sd.next();
int length = num.length();
sd.close();
if(length<7){
System.out.println("你输入的数字少于7位！");
}else{
GetValue gv =new GetValue(num);
}
}
}
题目33
package SU;
/**
* @ClassName PascalTriangle
* @Description 打印出杨辉三角形（要求打印出10行如下图）
* @Author TumTam
* @Date 2019/8/23 8:44
* @Version 1.0
**/
public class PascalTriangle {
public PascalTriangle(int a){
int x = 2*a;
int[][] array = new int [x][x];
int middle = (x/2)+1;
array[0][middle] = 1;
for(int i=1;i<a;i++){
for(int j=1;j<x;j++){
array[i][j-1] = array[i-1][j-1] + array[i-1][j];
}
}
for(int i=0;i<a;i++){
for(int j=0;j<x;j++){
if(array[i][j]==0){
System.out.print(" ");
}else{
System.out.print(array[i][j]+" ");
}
}
System.out.println();
}
}
}
package SU;
import java.util.Scanner;
public class PascalTriangleTest {
public static void main(String[] args) {
System.out.println("你想输入几行杨辉三角：");
Scanner sc =new Scanner(System.in);
int num = sc.nextInt();
sc.close();
PascalTriangle pt =new PascalTriangle(num);
}
}
题目34
package SU;
/**
* @ClassName OrderOutput
* @Description 输入3个数a,b,c，按大小顺序输出。
* @Author TumTam
* @Date 2019/8/23 11:30
* @Version 1.0
**/
public class OrderOutput {
public OrderOutput(int a,int b,int c) {
int temp;
if(b<c){
temp = b;
b = c;
c = temp;
}
if(a<c){
temp = a;
a = c;
c = temp;
}
if(a<b){
temp = a;
a = b;
b = temp;
}
System.out.println("从大到小输出：");
System.out.println(a+">"+b+">"+c);
}
}
package SU;
import java.util.Scanner;
public class OrderOutputTest {
public static void main(String[] args) {
System.out.println("请输入三个数：");
Scanner sss =new Scanner(System.in);
int a = sss.nextInt();
int b = sss.nextInt();
int c = sss.nextInt();
sss.close();
OrderOutput oo =new OrderOutput(a,b,c);
}
}
题目35
package SU;
import static java.lang.Integer.MAX_VALUE;
import static java.lang.Integer.MIN_VALUE;
/**
* @ClassName ArrayChange
* @Description 输入数组，最大的与第一个元素交换，最小的与最后一个元素交换，输出数组。
* @Author TumTam
* @Date 2019/8/26 12:44
* @Version 1.0
**/
public class ArrayChange {
public ArrayChange(int[] array){
int max = MIN_VALUE;
int maxid = 0;
int min = MAX_VALUE;
int minid = 0;
int temp;
for(int i=0;i<array.length;i++){
if(array[i]>max){
max = array[i];
maxid = i;
}
if(array[i]<min){
min = array[i];
minid = i;
}
}
temp = array[0];
array[0] = array[maxid];
array[maxid] = temp;
temp = array[array.length-1];
array[array.length-1] = array[minid];
array[minid] = temp;
for(int a:array){
System.out.print(a+" ");
}
}
}
package SU;
import java.util.Scanner;
public class ArrayChangeTest {
public static void main(String[] args) {
System.out.println("你想输入几个值：");
Scanner dc = new Scanner(System.in);
int a = dc.nextInt();
int[] array = new int[a];
System.out.println("请输入：");
for(int i=0;i<a;i++){
array[i] = dc.nextInt();
}
dc.close();
ArrayChange ac = new ArrayChange(array);
}
}
题目36
package SU;
/**
* @ClassName ArrayMove
* @Description 有n个整数，使其前面各数顺序向后移m个位置，最后m个数变成最前面的m个数
* @Author TumTam
* @Date 2019/8/26 13:09
* @Version 1.0
**/
public class ArrayMove {
public ArrayMove(int[] array,int m){
int[] arraylist = new int[array.length];
for(int i=0;i<m;i++){
arraylist[i] = array[array.length-m+i];
}
for(int i=m;i<array.length;i++){
arraylist[i] = array[i-m];
}
System.out.println("变更后的结果为：");
for(int a:arraylist){
System.out.println(a+" ");
}
}
}
package SU;
import java.util.Scanner;
public class ArrayMoveTest {
public static void main(String[] args) {
System.out.println("你要输入几个数：");
Scanner sc = new Scanner(System.in);
int a = sc.nextInt();
int[] array = new int[a];
System.out.println("请输入：");
for(int i=0;i<array.length;i++){
array[i] = sc.nextInt();
}
System.out.println("请问想要将前几位数后移：");
int m = sc.nextInt();
sc.close();
if(m>array.length){
m = m - array.length;
}
ArrayMove am = new ArrayMove(array,m);
}
}
题目37
package SU;
import java.util.HashMap;
import java.util.Map;
/**
* @ClassName NumberOff
* @Description 有n个人围成一圈，顺序排号。
* 从第一个人开始报数（从1到3报数），凡报到3的人退出圈子，
* 问最后留下的是原来第几号的那位。
* @Author TumTam
* @Date 2019/8/26 13:44
* @Version 1.0
**/
public class NumberOff {
public NumberOff(int num){
Map<Integer, Boolean> map = new HashMap<>(num);
for(int i=0;i<num;i++){
map.put((i+1),true);
}
int b = num;
int count=1;
int cun = 0;
while(b>1){
for(int i=0;i<num;i++){
int x=i+1;
if(map.get(x)){
if(count==3){
map.put(x,false);
b--;
count = 1;
}else{
count++;
}
}
}
}
for(int i:map.keySet()){
if(map.get(i)){
System.out.println("最后一人为原先的"+i+"号");
}
}
}
}
package SU;
import java.util.Scanner;
public class NumberOffTest {
public static void main(String[] args) {
System.out.println("请输入人数：");
Scanner sc =new Scanner(System.in);
int a = sc.nextInt();
NumberOff no =new NumberOff(a);
}
}
题目38
package SU;
/**
* @ClassName LengthCount
* @Description 写一个函数，求一个字符串的长度，在main函数中输入字符串，并输出其长度。
* @Author TumTam
* @Date 2019/8/26 14:39
* @Version 1.0
**/
public class LengthCount {
public LengthCount(StringBuffer sb){
int num = sb.length();
System.out.println("字符串的长度为："+num);
}
}
package SU;
import java.util.Scanner;
public class LengthCountTest {
public static void main(String[] args) {
System.out.println("请输入字符串：");
Scanner sc =new Scanner(System.in);
String s = sc.nextLine();
sc.close();
StringBuffer sb =new StringBuffer(s);
LengthCount lc =new LengthCount(sb);
}
}
题目39
package SU;
import org.apache.commons.lang3.ArrayUtils;
/**
* @ClassName OddNumberOrNot
* @Description 编写一个函数，输入n为偶数时。
* 调用函数求1/2+1/4+...+1/n,当输入n为奇数时，调用函数1/1+1/3+...+1/n(利用指针函数)
* @Author TumTam
* @Date 2019/8/26 15:04
* @Version 1.0
**/
public class OddNumberOrNot {
public OddNumberOrNot(int num){
int b = 2;
int[] array = new int[0];
double sum = 0;
if(num%2==0){
for(int i =b;i<=num;i+=b){
array = ArrayUtils.add(array,i);
}
}else{
for(int i =1;i<=num;i+=b){
array = ArrayUtils.add(array,i);
}
}
for(int i=0;i<array.length-1;i++){
int x = array[0];
double t =(double) 1/x;
sum=sum + t;
System.out.print(("1/"+x)+"+");
}
int y = array[array.length-1];
double te = (double) 1/y;
System.out.print("1/"+y+"="+(sum+te));
}
}
package SU;
import java.util.Scanner;
public class OddNumberOrNotTest {
public static void main(String[] args) {
System.out.println("请输入一个数：");
Scanner sc =new Scanner(System.in);
int a = sc.nextInt();
sc.close();
OddNumberOrNot onon =new OddNumberOrNot(a);
}
}
题目40
package SU;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
/**
* @ClassName StringSort
* @Description 字符串排序。
* @Author TumTam
* @Date 2019/8/26 16:23
* @Version 1.0
**/
public class StringSort {
public StringSort(List list){
Collections.sort(list, new Comparator() {
@Override
public int compare(String o1, String o2) {
return o1.compareTo(o2);
}
});
for(String key : list){
System.out.print(key+" ");
}
}
}
package SU;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class StringSortTest {
public static void main(String[] args) {
List<String> list = new ArrayList<>(16);
System.out.println("你想输入几个字符串：");
Scanner sc = new Scanner(System.in);
int a = sc.nextInt();
System.out.println("请输入:");
for(int i=0;i<a;i++){
list.add(sc.next());
}
StringSort ss = new StringSort(list);
}
}
题目41
package SU;
/**
* @ClassName MonkeyAndPeach
* @Description 海滩上有一堆桃子，五只猴子来分。
* 第一只猴子把这堆桃子凭据分为五份，多了一个，这只猴子把多的一个扔入海中，拿走了一份。
* 第二只猴子把剩下的桃子又平均分成五份，又多了一个，它同样把多的一个扔入海中，拿走了一份，
* 第三、第四、第五只猴子都是这样做的，问海滩上原来最少有多少个桃子？
* @Author TumTam
* @Date 2019/9/6 8:59
* @Version 1.0
**/
public class MonkeyAndPeach {
int sum =0;
public int countPeach(int n){
if(n==1){
return 1;
}else{
n--;
sum+=(countPeach(n)*5+1);
return sum;
}
}
}
package SU;
public class MonkeyAndPeachTest {
public static void main(String[] args) {
MonkeyAndPeach map =new MonkeyAndPeach();
int a =map.countPeach(5);
System.out.println("原本最少有"+a+"个桃子。");
}
}
题目42
package SU;
/**
* @ClassName ForAnswer
* @Description 809*??=800*??+9*??+1
* 其中??代表的两位数,8*??的结果为两位数，9*??的结果为3位数。
* 求??代表的两位数，及809*??后的结果。
* @Author TumTam
* @Date 2019/9/6 10:48
* @Version 1.0
**/
public class ForAnswer {
public void askQuestion(){
System.out.println("符合要求的数有：");
for(int i=10;i<100;i++){
int left =809*i;
int right =800*i+9*i+1;
int r1 =8*i;
int r2 =9*i;
boolean a = (left == right);
boolean b = (Judget(r1)==2);
boolean c = (Judget(r2)==3);
if(a && b && c){
System.out.print(i+" ");
}else{
System.out.println("没有符合要求的数。");
}
}
}
public int Judget(int a){
StringBuffer sb =new StringBuffer();
sb.append(a);
int len = sb.length();
return len;
}
}
package SU;
public class ForAnswerTest {
public static void main(String[] args) {
ForAnswer fa =new ForAnswer();
fa.askQuestion();
}
}
题目43
package SU;
/**
* @ClassName DiyOdd
* @Description 求0—7所能组成的奇数个数。
* @Author TumTam
* @Date 2019/9/6 11:12
* @Version 1.0
**/
public class DiyOdd {
public int sumOdd(){
int sum =0;
for(int i=1;i<=8;i++){
if(i==1){
sum+=4;
}else if(i==2){
sum+=(4*7);
}else{
int temp = ressult(i-2);
sum+=(4*7*temp);
}
}
return sum;
}
public int ressult(int n){
int r =1;
for(int i=0;i
r = r*8;
}
return r;
}
}
package SU;
public class DiyOddTest {
public static void main(String[] args) {
DiyOdd dod =new DiyOdd();
int all = dod.sumOdd();
System.out.println("一共可以组成"+all+"个奇数。");
}
}
题目44
package SU;
/**
* @ClassName EvenResolve
* @Description 一个偶数总能表示为两个素数之和。
* @Author TumTam
* @Date 2019/9/6 12:42
* @Version 1.0
**/
public class EvenResolve {
public boolean dept(int a){
boolean bo;
if(a%2 == 0){
bo = true;
}else{
bo = false;
}
return bo;
}
public boolean prim(int b){
boolean bo = true;
for(int i=2;i<b;i++){
if(b%i==0){
bo = false;
break;
}
}
return bo;
}
public void resolve(int c){
boolean a = dept(c);
int count = 0;
if(a){
for(int i=1;i<(c/2);i++){
boolean b = prim(i);
if(b){
int bb = c-i;
boolean p = prim(bb);
if(p){
System.out.println(c+"="+i+"+"+bb);
count++;
}
}
}
if(count==0){
System.out.println("此偶数无法分解为素数加法。");
}
}else{
System.out.println("这不是一个偶数。");
}
}
}
package SU;
import java.util.Scanner;
public class EvenResolveTest {
public static void main(String[] args) {
System.out.println("请输入一个偶数：");
Scanner sc =new Scanner(System.in);
int a = sc.nextInt();
sc.close();
EvenResolve er =new EvenResolve();
er.resolve(a);
}
}
题目45
package SU;
/**
* @ClassName DivideExactly
* @Description 判断一个素数能被几个9整除
* 首先，这个题目我就看不懂，素数怎么被9整除？
* 所以就忽略整除这个点了，不然真不知道怎么做。
* @Author TumTam
* @Date 2019/9/6 13:20
* @Version 1.0
**/
public class DivideExactly {
public boolean prim(int b){
boolean bo = true;
for(int i=2;i<b;i++){
if(b%i==0){
bo = false;
break;
}
}
return bo;
}
public void sout(int a){
boolean b = prim(a);
int countt = 0;
if(b){
while(a>=9){
a = a/9;
countt++;
}
}else{
System.out.println("你输入的不是素数。");
}
System.out.println("该素数比9的"+countt+"次方大");
}
}
package SU;
import java.util.Scanner;
public class DivideExactlyTest {
public static void main(String[] args) {
System.out.println("请输入一个素数：");
Scanner sc =new Scanner(System.in);
int a = sc.nextInt();
sc.close();
DivideExactly de =new DivideExactly();
de.sout(a);
}
}
题目46
package SU;
/**
* @ClassName StringLink
* @Description 两个字符串连接程序
* @Author TumTam
* @Date 2019/9/6 13:47
* @Version 1.0
**/
public class StringLink {
public String stringResult(String s1,String s2){
String str = s1 + s2;
return str;
}
}
package SU;
import java.util.Scanner;
public class StringLinkTest {
public static void main(String[] args) {
System.out.println("请输入两个字符串：");
Scanner sc = new Scanner(System.in);
String a = sc.next();
String b = sc.next();
sc.close();
StringLink sl = new StringLink();
String s = sl.stringResult(a,b);
System.out.println(s);
}
}
题目47
package SU;
/**
* @ClassName PrintStars
* @Description 读取7个数（1—50）的整数值，每读取一个值，程序打印出该值个数的＊。
* @Author TumTam
* @Date 2019/9/6 13:57
* @Version 1.0
**/
public class PrintStars {
public void printStar(int a){
for(int i=0;i<a;i++){
System.out.print("*");
}
System.out.println();
}
}
package SU;
import java.util.Scanner;
public class PrintStarsTest {
public static void main(String[] args) {
System.out.println("请输入一到五十以内的7个整数：");
Scanner sc = new Scanner(System.in);
PrintStars ps = new PrintStars();
for(int i=0;i<7;i++){
ps.printStar(sc.nextInt());
}
sc.close();
}
}
题目48
package SU;
/**
* @ClassName encryption
* @Description 某个公司采用公用电话传递数据，数据是四位的整数，
* 在传递过程中是加密的，加密规则如下：
* 每位数字都加上5,然后用和除以10的余数代替该数字，
* 再将第一位和第四位交换，第二位和第三位交换。
* @Author TumTam
* @Date 2019/9/6 14:57
* @Version 1.0
**/
public class encryption {
public String encry(int a) {
StringBuffer sb = new StringBuffer();
sb.append(a);
for (int i = 0; i < 4; i++) {
char b = sb.charAt(i);
int cc = b + 5 -'0';
int ccc = cc%10;
char c = String.valueOf(ccc).charAt(0);
sb.setCharAt(i, c);
}
char c = sb.charAt(0);
sb.setCharAt(0, sb.charAt(3));
sb.setCharAt(3, c);
char b = sb.charAt(1);
sb.setCharAt(1, sb.charAt(2));
sb.setCharAt(2, b);
String str = sb.toString();
return str;
}
}
package SU;
import java.util.Scanner;
public class encryptionTest {
public static void main(String[] args) {
System.out.println("请输入一个四位数：");
Scanner sc = new Scanner(System.in);
int a = sc.nextInt();
sc.close();
encryption e = new encryption();
String s = e.encry(a);
System.out.println(s);
}
}
题目49
package SU;
/**
* @ClassName CharCount
* @Description 计算字符串中子串出现的次数
* @Author TumTam
* @Date 2019/9/9 8:31
* @Version 1.0
**/
public class CharCount {
public int charC(String c){
int num =0;
String[] s = c.split(" ");
num = s.length;
return num;
}
}
package SU;
import java.util.Scanner;
public class CharCountTest {
public static void main(String[] args) {
System.out.println("请输入多条字符串，以空格分隔：");
Scanner sc = new Scanner(System.in);
String s = sc.nextLine();
sc.close();
CharCount cc = new CharCount();
int num = cc.charC(s);
System.out.println("该字符串中有"+num+"个子字符串。");
}
}
题目50
package SU;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
/**
* @ClassName IO
* @Description 有五个学生，每个学生有3门课的成绩，从键盘输入以上数据（包括学生号，姓名，三门课成绩），计算出平均成绩，将原有的数据和计算出的平均分数存放在磁盘文件"stud"中。
* @Author TumTam
* @Date 2019/9/9 8:44
* @Version 1.0
**/
public class IO {
public void doIO(List<LinkedHashMap<String,String>> list) throws IOException {
File file = new File("D:\\stud.txt");
FileOutputStream out = new FileOutputStream(file,true);
OutputStreamWriter osw = new OutputStreamWriter(out, "UTF-8");
for(LinkedHashMap<String,String> map :list){
Iterator<String> it = map.keySet().iterator();
while(it.hasNext()){
String key = it.next();
String str = key+":"+map.get(key);
osw.write(str+"\r\n");
}
osw.write("\r\n");
}
osw.close();
}
}
package SU;
import java.io.IOException;
import java.util.*;
public class IOTest {
public static void main(String[] args)throws IOException {
System.out.println("请输入你想录入多少学生的成绩：");
Scanner sc =new Scanner(System.in);
int a = sc.nextInt();
List> list =new ArrayList<>();
for(int i=0;i
LinkedHashMap map =new LinkedHashMap<>(16);
System.out.println("输入第"+(i+1)+"个学生的信息：");
System.out.println("学号：");
map.put("学号",sc.next());
System.out.println("姓名：");
map.put("姓名",sc.next());
System.out.println("语文成绩：");
String f = sc.next();
map.put("语文成绩",f);
System.out.println("数学成绩：");
String s = sc.next();
map.put("数学成绩",s);
System.out.println("英语成绩：");
String t = sc.next();
map.put("英语成绩",t);
int avg = (Integer.parseInt(f)+Integer.parseInt(s)+Integer.parseInt(t))/3;
String avge = avg +"";
map.put("平均成绩",avge);
list.add(i,map);
}
IO io =new IO();
io.doIO(list);
}
}
终于写完了，如果哪里有错有缺失，欢迎指正~
