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practical_exercises/10_day_practice/day7/二元运算符/1.类运算符重载.cpp

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+//有复数类Complex，利用运算符重载实现复数的加、减、乘、除等复数运算。
+#include<iostream>
+using namespace std;
+class Complex {
+    private:
+        double r,i;
+    public:
+        Complex(double R=0,double I=0):r(R),i(I){};
+        Complex operator+(Complex b);
+        Complex operator-(Complex b);
+        Complex operator*(Complex b);
+        Complex operator/(Complex b);
+        void display();
+};
+
+Complex Complex::operator +(Complex b)
+{
+    return Complex(r+b.r,i+b.i);
+}
+Complex Complex::operator -(Complex b)
+{
+    return Complex(r-b.r,i-b.i);
+}
+//求复数相乘的算法
+Complex Complex::operator *(Complex b)
+{   
+    Complex t;
+    t.r=r*b.r-i*b.i;
+    t.i=r*b.i+i*b.r;
+    return t;
+}
+//求复数相除的算法
+Complex Complex::operator /(Complex b) {
+    Complex t;
+    double x;
+    x=1/(b.r*b.r+b.i*b.i);
+    t.r=x*(r*b.r+i*b.i);
+    t.i=x*(i*b.r-r*b.i);
+    return t;
+}
+void Complex::display(){
+    cout<<r;
+    if (i>0) cout<<"+";
+    if (i!=0) cout<<i<<"i"<<endl;
+    //}display();
+};
+
+int main(void) {
+    Complex c1(1,2),c2(3,4),c3,c4,c5,c6;
+    Complex a,b(2,3);
+    a=b+2;       			//正确
+    // a=2+b;       			//错误   
+    a.display();  
+    c3=c1+c2;
+    c4=c1-c2;
+    c5=c1*c2;
+    c6=c1/c2;
+    c1.display();
+    c2.display();
+    c3.display();
+    c4.display();
+    c5.display();
+    c6.display();
+    system("pause");
+    return 0;
+}
+

practical_exercises/10_day_practice/day7/二元运算符/2.友元运算符实现.cpp

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+
+/*
+在C++的标准命名空间std中预定义了复数类Complex，
+并且通过友元重载了Complex的各种运算，包括本程序中重载的+、-、*、/。
+若使用using namespace std将std名字空间引入本程序，
+则本程序中的Complex将与std名字空间中的Complex类的运算符重载函数产生冲突，引起编译错误。
+*/
+/*
+对于不要求左值且可以交换参数次序的运算符（如+、-、*、/ 等运算符），
+最好用非成员形式（包括友元和普通函数）的重载运算符函数实现。
+*/
+
+//解决前面的2+b问题。
+#include<iostream>
+
+
+class Complex{
+    private:
+        double r,i;
+    public:
+        Complex(double R=0,double I=0):r(R),i(I){};
+        friend Complex operator+(Complex a, Complex b);
+        friend Complex operator-(Complex a, Complex b);
+        friend Complex operator*(Complex a, Complex b);
+        friend Complex operator/(Complex a, Complex b);
+
+        friend Complex operator+(Complex a,double b){
+            return Complex(a.r+b,a.i);
+        }
+        friend Complex operator+(double a,Complex b){
+            return Complex(a+b.r,b.i);
+        }
+        
+        void display();
+};
+
+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);
+}
+Complex operator*(Complex a, Complex b){
+    Complex t;
+    t.r = a.r*b.r-a.i*b.i;
+    t.i = a.r*b.i+a.i*b.r;
+}
+Complex operator/(Complex a, Complex b){
+    Complex t;
+    double x;
+    x = 1/(b.r*b.r+b.i*b.i);
+    t.r = x*(a.r*b.r+a.i*b.i);
+    t.i = x*(a.i*b.r-a.r*b.i);
+    return t;
+}
+
+void Complex::display(){
+    std::cout<<r;
+    if(i>0)
+        std::cout<<"+";
+    if(i!=0)
+        std::cout<<i<<"i"<<std::endl;
+}
+int main(void) {
+    Complex c1(1,2),c2(3,4),c3,c4,c5,c6; 
+    Complex a,b(2,3);
+    Complex a1=b+2;       			
+    Complex a2=2+b;       	 
+    a1.display();
+    a2.display();  
+    c3=c1+c2;
+    c4=c1-c2;
+    c5=c1*c2;
+    c6=c1/c2;
+    c1.display();
+    c2.display();
+    c3.display();
+    c4.display();
+    c5.display();
+    c6.display();
+    system("pause");
+    return 0;
+}
+