C++学习（5）

关于类的运算符重载：

分为两种： 1）将运算符重载为类的友元函数

　　　　　　2）将运算符重在为类的成员函数

一：

 1 //friend 函数类型   operator 运算符(形参表){}
 2 //通过重载 ，进行复数运算
 3 #include <iostream>
 4 using namespace std;
 5 
 6 class Complex
 7 {
 8     private:
 9         double real;
10         double image;
11     public:
12     Complex(double real=0.0,double image=0.0)
13     {
14         this->real=real;
15         this->image=image;
16     }
17     void display()
18     {
19         cout<<"("<<real<<","<<image<<")"<<endl;
20     }
21     friend Complex operator + (Complex A, Complex B)
22     {
23         return Complex (A.real+B.real,A.image+B.image);
24     }
25     friend Complex operator - (Complex A, Complex B);
26     friend Complex operator - (Complex A);      //  重载取负为友元函数
27     friend Complex operator ++ (Complex &A);    //  重载前置++为友元函数
28     friend Complex operator ++ (Complex &A, int); // 重载后置++为友元函数
29 };
30 
31 Complex operator -(Complex A,Complex B)
32 {
33     return Complex(A.real-B.real,A.image-B.image);
34 }
35 
36 Complex operator -(Complex A)
37 {
38     return Complex(-A.real,-A.image);
39 }
40 
41 Complex operator ++(Complex &A)
42 {
43     return Complex(++A.real,A.image);
44 }
45 
46 Complex operator ++(Complex &A,int)
47 {
48     return Complex(A.real++,A.image);
49 }
50 
51 int main()
52 {
53     Complex A(100.0,200.0),B(-10.0,20.0),C;
54     cout<<"A=", A.display();
55     cout<<"B=", B.display();
56     C=A+B;
57     cout<<"C=A+B=", C.display();
58     C=A-B;
59     cout<<"C=A-B=", C.display();
60     C=-A+B;
61     cout<<"C=-A+B", C.display();
62     C=A++;
63     cout<<"C=A++, C=", C.display();
64     C=++A;
65     cout<<"C=++A, C=", C.display();
66     C=A+5;
67     C.display();
68     return 0;
69 }

二：

 1 //重载为类的成员函数
 2 // 返回类型 类名::operator 运算符（形参表）
 3 #include <iostream>
 4 using namespace std;
 5 class Complex
 6 {
 7     private:
 8         double real;
 9         double image;
10     public:
11         Complex(double real=0.0,double image=0.0)
12         {
13             this->real=real;
14             this->image=image;
15         }
16         void display()
17         {
18             cout<<"("<<real<<","<<image<<")"<<endl;
19         }
20         Complex operator + (Complex B);
21         Complex operator - (Complex B);
22         Complex operator - ();          //取负重载成员函数
23         Complex operator ++ ();         //前置++重载成员函数
24         Complex operator ++ (int);      //后置--重载成员函数
25 
26 };
27 Complex Complex::operator + (Complex B)
28 {
29     return Complex(real+B.real,image+B.image);
30 }
31 
32 Complex Complex::operator - (Complex B)
33 {
34     return Complex(real+B.real,image+B.image);
35 }
36 
37 Complex Complex::operator - ()
38 {
39     return Complex(-real,-image);
40 }
41 
42 Complex Complex::operator ++()
43 {
44     return Complex(++real,image);
45 }
46 
47 Complex Complex::operator ++(int)
48 {
49     return Complex(real++,image);
50 }
51 
52 int main()
53 {
54     Complex A(100.0,200.0),B(-10.0,20.0),C;
55     cout<<"A=", A.display();
56     cout<<"B=", B.display();
57     C=A+B;
58     cout<<"C=A+B=", C.display();
59     C=A-B;
60     cout<<"C=A-B=", C.display();
61     C=-A+B;
62     cout<<"C=-A+B", C.display();
63     C=A++;
64     cout<<"C=A++, C=", C.display();
65     C=++A;
66     cout<<"C=++A, C=", C.display();
67     C=A+5;
68     C.display();
69     return 0;
70 }