C++友元函数学习笔记
作者:互联网
Complex &operator++() {
real += 1;
vir += 1;
return *this;
}
其中&的作用是为了解决(++com)++的问题,com是Complex的一个对象,如果不加&那么++com返回值就不止com本身,之后的com++就不会在com的基础上++,最后cout << com;就只加了一个1,如果加了&就加了两个1
ostream &operator<<(ostream &out, const Complex &com) {}
其中&的作用是为了实现连续输出。
Complex &operator++(int);与Complex &operator++();的区别
第一个是处理++com的情况,第二个是处理com++的情况
想要返回值只能被访问不能被修改则在函数最前面加一个const
例:
const int operator[](...) const {}
以下是自己实现的一个复数类代码
#include<iostream>
using namespace std;
class Complex {
public:
Complex(int real, int vir) : real(real), vir(vir) {
cout << "Constructor : " << this << endl;
}
Complex operator+(int val) {
return Complex(real + val, vir + val);
}
Complex operator++(int val) {
Complex ret(*this);
real += 1;
vir += 1;
return ret;
}
Complex &operator++() {
real += 1;
vir += 1;
return *this;
}
Complex operator--(int val) {
Complex ret(*this);
real -= 1;
vir -= 1;
return ret;
}
Complex &operator--() {
real -= 1;
vir -= 1;
return *this;
}
Complex operator-(int val) {
return Complex(real - val, vir - val);
}
Complex operator*(int val) {
return Complex(real * val, vir * val);
}
Complex operator/(int val) {
return Complex(real / val, vir / val);
}
friend Complex operator+(const Complex &, const Complex &);
friend Complex operator*(const Complex &, const Complex &);
friend Complex operator/(const Complex &, const Complex &);
friend Complex operator-(const Complex &, const Complex &);
friend void output(Complex &);
friend ostream &operator<<(ostream &, const Complex &);
private:
int real, vir;
};
Complex operator+(const Complex &a, const Complex &b) {
return Complex(a.real + b.real, a.vir + b.vir);
}
Complex operator-(const Complex &a, const Complex &b) {
return Complex(a.real - b.real, a.vir - b.vir);
}
Complex operator*(const Complex &a, const Complex &b) {
return Complex(a.real * b.real, a.vir * b.vir);
}
Complex operator/(const Complex &a, const Complex &b) {
return Complex(a.real / b.real, a.vir / b.vir);
}
void output(Complex &a) {
cout << a.real << "\t" << a.vir << endl;
return ;
}
ostream &operator<<(ostream &out, const Complex &a) {
out << a.real << "\t" << a.vir;
return out;
}
int main() {
Complex com(4, 5);
output(com);
cout << com + 5 << endl;
cout << (++com)++ << endl;
cout << com << endl;
Complex com1(2, 3);
cout << com * com1 << endl;
return 0;
}
标签:友元,++,笔记,vir,int,Complex,C++,operator,com 来源: https://blog.csdn.net/qqQQqsadfj/article/details/120390770