程序设计与算法（三）C++面向对象程序设计 第四周 相关笔记

1、

运算符重载

#include<bits/stdc++.h>
using namespace std;
class Complex{
    public:
        double r,i;
        Complex(double rr = 0,double ii = 0):r(rr),i(ii){}
        Complex operator-(Complex&b);
        void output(){
            cout<<r<<" "<<i<<endl;
        }
}; 
Complex operator+(Complex &a,Complex &b){
    return Complex(a.r+b.r,a.i+b.i);
}
Complex operator*(Complex &a,Complex &b){
    return Complex(a.r*b.r-a.i*b.i,a.r*b.i+a.i*b.r);
}
Complex Complex::operator-(Complex&b){
    return Complex(r-b.r,i-b.i);
}
int main(){
    Complex a(1,3),b(4,5),c;
    c = a+b;
    c.output();
    c = a-b;
    c.output();
    c = a*b;
    c.output();
    return 0;
} 

输出：
5 8
-3 -2
-11 17

 2、

赋值运算符的重载

#include<bits/stdc++.h>
using namespace std;
class Complex{
    public:
        double r,i;
        Complex(double rr = 0,double ii = 0):r(rr),i(ii){}
        void output(){
            cout<<r<<" "<<i<<endl;
        }
        void operator=(double rr);
}; 
void Complex::operator=(double rr){
    r = rr;
}
int main(){
    Complex a;
    a = 2;
    a.output();
    a = 2.214;
    a.output();
    
    return 0;
} 

3、

运算符重载为友元

#include<bits/stdc++.h>
using namespace std;
class Complex{
    private:
        double r,i;
    public:
        
        Complex(double rr = 0,double ii = 0):r(rr),i(ii){}
        void output(){
            cout<<r<<" "<<i<<endl;
        }
        void operator=(double rr);
        Complex operator+(double add){
            return Complex(r+add,i);
        }
        friend Complex operator+(double add,Complex &a);
}; 
void Complex::operator=(double rr){
    r = rr;
}
Complex operator+(double add,Complex &a){
    return Complex(add+a.r,a.i);
}
int main(){
    Complex a(2,3);
    a.output();
    a = a+2;
    a.output();
    a = 2+a;
    a.output();
    return 0;
} 
输出：
2 3
4 3
6 3

4、

类型转换运算符的重载

#include<bits/stdc++.h>
using namespace std;
class Complex{
    private:
        double r,i;
    public:
        
        Complex(double rr = 0,double ii = 0):r(rr),i(ii){}
        operator double(){
            return r;
        }
}; 

int main(){
    Complex a(2,3);
    cout<<(double)a<<endl;
    double n = 3 + a;
    cout<<n<<endl;
    return 0;
} 

5、

++ --的重载

#include<bits/stdc++.h>
using namespace std;
class Complex{
    private:
        double r,i;
    public:
        
        Complex(double rr = 0,double ii = 0):r(rr),i(ii){}
        operator double(){
            return r;
        }
        Complex operator++(){
            r++;
            return Complex(r,i);
        }
}; 

int main(){
    Complex a(2,3);
    cout<<(double)a<<endl;
    cout<<(++a)<<endl;
    return 0;
}