9月16日总结

1.给类重载 <<

 

#include <iostream>using namespace std;class A{public:A(int a,int b){x=a;y=b;}friend ostream & operator << (ostream & s,const A & c) //声明友元 另一个类的对象比如ostream类的cout对象就可以以朋友的身份访问A的私有成员。{s<<c.x;s<<c.y;return s;}private:int x;int y;};int main(){A a(3,4),b(5,6);cout<<a<<b;return 0;}

2.在堆中释放字符串

删除在堆中创建的字符串 delete []ch;

3.复习自加和自减运算符

/* 功能：演示自加运算符 结果：++a是先取值后自加，a++是先取值后自加 */#include <iostream>using namespace std;int main(){int a=4;cout<<"cout<<a++"<<" "<<a++<<endl; a=4;cout<<"cout<<++a"<<" "<<++a<<endl;return 0;}

 

3.给类重载 >>

/* 重载运算符 >> */#include <iostream>using namespace std;class A{public:A(int s){x=s;}friend istream &operator>>(istream &s,A&c){cin>>c.x;return s;}friend ostream &operator<<(ostream &s,A&c){cout<<c.x;return s;}private:int x;};int main(){A a(3);cout<<a;cin>>a;cout<<a;return 0;}