学习内容
- 掌握类的定义
- 掌握对象的定义和方法调用
- 熟悉构造函数和析构函数的定义和执行过程
- 掌握复制构造函数和初始化列表的使用
实习任务
-
实习任务一
注意全局对象的生命周期
#include <iostream>
using namespace std;
class TestClass{
public:
TestClass(int a){
aa=a;
cout<<aa<<" Constructed!\n";
}
~TestClass(){
cout<<aa<<" Destructed!\n";
}
private:
int aa;
};
TestClass AA(3);
int main(){
//全局对象
cout<<"In MainFuction."<<endl;
TestClass BB(5);
return 0;
}
运行结果:
3 Constructed!
In MainFuction.
5 Constructed!
5 Destructed!
3 Destructed!
[Finished in 0.3s]
#include <iostream>
using namespace std;
class TestClass{
public:
TestClass(){
cout<<" Constructed!\n";
}
~TestClass(){
cout<<" Destructed!\n";
}
};
int main(){
TestClass t1;
TestClass *p;
p=new TestClass;
delete p;
return 0;
}
运行结果：
Constructed!
Constructed!
Destructed!
Destructed!
[Finished in 0.3s]
#include <iostream>
using namespace std;
class TestClass{
public:
TestClass(){
cout<<" Constructed!\n";
value = 10;
}
~TestClass(){
cout<<" Destructed!\n";
}
void setValue(int newValue){
value = newValue;
}
int getValue()const{
return value;
}
private:
int value;
};
int main(){
TestClass t1;
cout<<t1.getValue()<<endl;
TestClass &rt1 = t1;
rt1.setValue(20);
cout<<t1.getValue()<<endl;
TestClass *pt=&t1;
pt->setValue(30); //a->b means (*a).b
// (*pt).setValue(30);//try uncomment this one
cout<<t1.getValue()<<endl;
return 0;
}
运行结果：
Constructed!
10
20
30
Destructed!
[Finished in 0.3s]
#include <iostream>
#include <vector>
using namespace std;
class Test{
public:
Test():a(1){
cout<<a<<endl;
}
Test(int a){
cout<<this->a<<endl;
this->a=a;
cout<<this->a<<endl;
}
private:
int a=3;
};
int main(){
Test t1;
Test t2(10);
return 0;
}
运行结果：
1
3
10
[Finished in 0.4s]
-
实习任务二
要求：编写 Complex 类，封装复数的基本功能
#include <iostream>
#include <cmath>
using namespace std;
class Complex{
public:
Complex(){
real = 0;
image = 0;
}
Complex(double n){
real = n;
image = 0;
}
Complex(double n, double d){
real = n;
image = d;
}
void setValue(double n, double d){
real = n;
image = d;
}
double getReal(){
return real;
}
double getImage(){
return image;
}
double getDistance(){
return sqrt(pow(real,2)-pow(image,2));
}
void output(){
if(image == 0 && real != 0){
cout<<real<<endl;
}
else if(image !=0 && real ==0){
cout<<image<<'i'<<endl;
}
else if(image == 0 && real == 0){
cout<<0<<endl;
}
else{
if(image<0){
cout<<real<<image<<'i'<<endl;
}
else{
cout<<real<<'+'<<image<<'i'<<endl;
}
}
}
private:
double real;
double image;
};
int main(){
Complex c1, c2(2), c3(3,4);
c1.output();
c2.output();
c3.output();
c1.setValue(6,4);
c1.output();
cout<<c1.getDistance()<<endl;
return 0;
}
运行结果：
0
2
3+4i
6+4i
4.47214
[Finished in 0.3s]
-
实习任务三
要求：编写 Time 类，封装对时间的操作，Time 类处理 1 天内的时间，精确到分钟。
#include <iostream>
using namespace std;
class Time{
public:
Time(){
hour = 0;
minute = 0;
}
Time(int h, int m){
hour = h;
minute = m;
}
void setTime(int h, int m){
hour = h;
minute = m;
}
void output(){
this->normalizeTime();
cout<<hour<<':'<<minute<<endl;
}
int getHour(){
return hour;
}
int getMinute(){
return minute;
}
int getTotalMinutes(){
return hour*60 + minute;
}
private:
int hour;
int minute;
void normalizeTime(){
hour = ((60*hour + minute)/60)%24;
minute = minute%60;
}
};
int main(){
Time t1(12, 75);
t1.output();
t1.setTime(8, 65);
t1.output();
cout<<"t1 Hour:"<<t1.getHour()<<endl;
cout<<"t1 Minute:"<<t1.getMinute()<<endl;
cout<<"t1 getTotalMinutes:"<<t1.getTotalMinutes()<<endl;
return 0;
}
运行结果：
13:15
9:5
t1 Hour:9
t1 Minute:5
t1 getTotalMinutes:545
[Finished in 0.3s]
-
实习任务四？
要求：编写随机数类。请实现所要求的成员函数。
#include <iostream>
#include <ctime>
using namespace std;
class RandomNum{
public:
RandomNum(unsigned int seed){
if(seed == 0){
srand((unsigned int)time(NULL));
}
else{
srand(seed);
}
}
void setSeed(unsigned int seed){
this->seed = seed;
}
int random(){
return rand();
}
int random(int max){
return rand()%max;
}
double frandom(){
return rand()/(double)RAND_MAX;
}
private:
unsigned int seed;
};
int main()
{
RandomNum randomGenerator(100);
int i;
for(int i=0; i<10; ++i){
cout<<randomGenerator.frandom()<<' ';
}
cout<<endl;
return 0;
}
运行结果：
0.000782637 0.153779 0.560532 0.865013 0.276724 0.895919 0.704462 0.886472 0.929641 0.46929
[Finished in 0.3s]
具体的有关c++随机数的内容可以看这里
