设计一个程序，将加法运算符和减法运算符分别重载为成员函数，使之能够实现复数的加法运算与减法运算。将乘法运算符和除法运算符分别重载为友元函数，使之能够实现复数的乘法运算与除法运算

以下是一个可能的实现：

#include<iostream>
using namespace std;

class Complex {
private:
    double real;
    double imag;
public:
    Complex(double r = 0.0, double i = 0.0): real(r), imag(i) {}
    Complex operator + (const Complex& c) {
        return Complex(real + c.real, imag + c.imag);
    }
    Complex operator - (const Complex& c) {
        return Complex(real - c.real, imag - c.imag);
    }
    friend Complex operator * (const Complex& c1, const Complex& c2);
    friend Complex operator / (const Complex& c1, const Complex& c2);
    void display() {
        cout << "(" << real << ", " << imag << ")" << endl;
    }
};

Complex operator * (const Complex& c1, const Complex& c2) {
    return Complex(c1.real * c2.real - c1.imag * c2.imag, c1.real * c2.imag + c1.imag * c2.real);
}

Complex operator / (const Complex& c1, const Complex& c2) {
    double r = c2.real * c2.real + c2.imag * c2.imag;
    return Complex((c1.real * c2.real + c1.imag * c2.imag) / r, (c1.imag * c2.real - c1.real * c2.imag) / r);
}

int main() {
    Complex a(1.0, 2.0);
    Complex b(3.0, 4.0);
    Complex c = a + b;
    c.display();
    Complex d = a - b;
    d.display();
    Complex e = a * b;
    e.display();
    Complex f = a / b;
    f.display();
    return 0;
}

在上面的代码中，我们定义了一个名为 Complex 的类，表示复数。该类重载了加法运算符和减法运算符作为成员函数，重载了乘法运算符和除法运算符作为友元函数。在 main 函数中，我们创建了两个复数 a 和 b，并测试了加减乘除四种运算。