运算符重载

运算符重载

成员函数单目

#include<iostream>
using namespace std;
class A{
	int p;
public:
	A (int a){
		p = a;
	}
	A operator++(){
        p++;
        return *this;
	}
	A operator++(int){
		A temp(*this);
		p++;
		return temp;
	}
	void show(){
		cout<<p<<endl;
	}
};
int main(int argc, char const *argv[])
{
	A a(10);
	++a;
	a++;
	a.show();
	return 0;
}

成员函数双目

#include<cstring>
#include<iostream>
using namespace std;
class A{
	int p;
public:
	A (int a){
		p = a;
	}
	A operator +(A& a);/*这里的&一定要用*/
	void show(){
		cout<<p<<endl;
	}
};
A A:: operator +(A& a){/*不用友元时，相当于用了一波this，强调一下他直接第一个调用*this*/
		A temp(0);/*这里不能用 A temp*/
		temp.p = p + a.p;
		return temp;
}
int main(int argc, char const *argv[])
{
	A a(10),b(5);
	A c = a + b;
    c.show();
	return 0;
}

友元函数单目

#include<cstdio>
#include<algorithm>
#include<cstring>
#include<iostream>
using namespace std;
class A{
	int p;
public:
	A(int a){
        p = a;
	};
	friend A operator ++(A &a){
       a.p++;
       return a;
	}
	friend A operator++(A &a,int){
		A temp = a;
		a.p++;
		return temp;
	}
    void show(){
		cout<<p<<endl;
	}
};
int main(int argc, char const *argv[])
{
	A a(10);
    a++;
    a.show();
	return 0;
}

友元函数双目

#include<cstdio>
#include<algorithm>
#include<cstring>
#include<iostream>
using namespace std;
class A{
	int p;
public:
	A(int a){
        p = a;
	};
	friend A operator +(A &a,A &b){
       A c(0);
       c.p = a.p + b.p;
       return c;
	}
    void show(){
		cout<<p<<endl;
	}
};
int main(int argc, char const *argv[])
{
	A a(10),b(10);
	A c = a + b; 
    c.show();
	return 0;
}