1、输入两个整数，打印两数之差的绝对值。
package com.javawu.demo;
import java.util.Scanner;
public class Demo1 {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("输入两个整数，用回车或者空格分隔");
Scanner scan = new Scanner(System.in);
int one = scan.nextInt();
int two = scan.nextInt();
if (one - two >= 0) {
System.out.println(one - two);
}else {
System.out.println(two - one);
}
}
}
2、编写一个四则运算器，计算加减乘除，例如输入10 + 20，输出30。
package com.javawu.demo;
import java.util.Scanner;
public class Demo2 {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("请输入一个四则运算，用空格分隔");
Scanner scan = new Scanner(System.in);
int numOne = scan.nextInt();
String str = scan.next();
int numTwo = scan.nextInt();
switch(str){
case "+":
System.out.println(numOne + numTwo);
break;
case "-":
System.out.println(numOne - numTwo);
break;
case "*":
System.out.println(numOne * numTwo);
break;
case "/":
System.out.println(numOne / numTwo);
break;
default:
System.out.println("格式错误");
}
}
}
3、输入年月日，计算是一年的第几天，考虑闰年。
package com.javawu.demo;
import java.util.Scanner;
public class Demo3 {
public static void main(String[] args){
System.out.println("请输入年月日，用空格分隔");
Scanner scan = new Scanner(System.in);
int year = scan.nextInt();
int month = scan.nextInt();
int day = scan.nextInt();
int total = 0;
for (int i = 1; i < month; i++) {
switch (i) {
case 1:
total += 31;
break;
case 2:
if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0) {
total += 29;
} else {
total += 28;
}
break;
case 3:
total += 31;
break;
case 4:
total += 30;
break;
case 5:
total += 31;
break;
case 6:
total += 30;
break;
case 7:
total += 31;
break;
case 8:
total += 31;
break;
case 9:
total += 30;
break;
case 10:
total += 31;
break;
case 11:
total += 30;
break;
case 12:
total += 31;
break;
}
}
System.out.println(total+day);
}
}
4、判断一个三位数是否是水仙花数,如果是,输出YES,如果不是,输出NO。
说明:水仙花就是一个数的每个数字的立方和等于它本身的数,例如153就是一个水仙花数111+555+333=153。
package com.javawu.demo;
import java.util.Scanner;
public class Demo4 {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("请输入一个三位数");
Scanner scan = new Scanner(System.in);
int num = scan.nextInt();
int hundreds = num/100;
int tens = num%100/10;
int ones = num%10;
if (num == hundreds*hundreds*hundreds + tens*tens*tens + ones*ones*ones) {
System.out.println("YES");
}else {
System.out.println("NO");
}
}
}
5、输入一个时间,输出时间的下一秒。例如输入的是10 20 59,表示是10点20分59秒,下一秒就是10点21分0秒。
package com.javawu.demo;
import java.util.Scanner;
public class Demo5 {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("请输入时分秒，用空格分隔");
Scanner scan = new Scanner(System.in);
int hours = scan.nextInt();
int minutes = scan.nextInt();
int second = scan.nextInt();
if (hours > 12 || minutes > 60 || second > 60) {
System.out.println("格式错误");
}else {
if (second + 1 == 60) {
minutes ++;
second = 0;
}else {
second ++;
}
if (minutes == 60) {
hours ++;
minutes = 0;
}else {
}
System.out.println(hours + "时" + minutes + "分" + second + "秒");
}
}
}
6、输入三个整数，x,y,z,把这三个数由小到大输出。
package com.javawu.demo;
import java.util.Scanner;
public class Demo6 {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("请输入三个整数，用空格隔开");
Scanner scan = new Scanner(System.in);
int a = scan.nextInt();
int b = scan.nextInt();
int c = scan.nextInt();
if (a > b) {
a = a + b;
b = a - b;
a = a - b;
}
if (b > c) {
b = b + c;
c = b - c;
b = b - c;
}
if (a > b) {
a = a + b;
b = a - b;
a = a - b;
}
System.out.println(a);
System.out.println(b);
System.out.println(c);
}
}
7、求1! + 2! + 3! +…+ 5!。
package com.javawu.demo;
public class Demo7 {
public static void main(String[] args) {
// TODO Auto-generated method stub
int num = 0;
for (int i = 1; i <= 5; i ++) {
for (int j = 1; j <= i; j ++) {
num = num + i * j;
}
}
System.out.println(num);
}
}
8、输入一个整数，计算该数有多少位 ，例如123有3位。
package com.javawu.demo;
import java.util.Scanner;
public class Demo8 {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("请输入一个整数");
Scanner scan = new Scanner(System.in);
int num = scan.nextInt();
int a = 1;
int time = 0;
while (num/a != 0) {
a = a * 10;
time ++;
}
System.out.println(time);
}
}
9、整数逆序输出,例如输入一个整数12345,输出整数54321。
package com.javawu.demo;
import java.util.Scanner;
public class Demo9 {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("请输入一个整数");
Scanner scan = new Scanner(System.in);
int num = scan.nextInt();
int a = 1;
int time = 0;
while (num/a != 0) {
a = a * 10;
time ++;
}
System.out.println(time);
int result = 0;
for (int i = 0; i <= time; i ++) {
int b = num / i * 10;
System.out.println(b);
result = result + (time - i+1) * b;
}
System.out.println(result);
}
}
10、打印九九乘法表。
package com.javawu.demo;
public class Demo10 {
public static void main(String[] args) {
// TODO Auto-generated method stub
for (int i = 1; i <= 9; i ++) {
for (int j = 1; j <= i; j ++) {
System.out.print(i + "*" + j + "=" + i * j + "\t");
}
System.out.println();
}
}
}
11、打印图形。
等腰三角形
package com.javawu.demo;
public class Demo11 {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println();
System.out.println();
for (int i = 1; i <= 6; i ++) {
System.out.print(" ");
System.out.print(" ");
for (int j = 1; j <= 6 - i; j ++) {
System.out.print(" ");
}
for (int k = 1; k <= i *2 -1; k ++) {
System.out.print("*");
}
System.out.println();
}
}
}
