c++定义一个复数类complex，重载运算符'+'、'-'、'*' ，使之能用于复数的加减乘，运算符重载函数作为complex类的成员函数， 分别求两个复数的和、差、 积。

好的，下面是C++实现：

#include <iostream>
using namespace std;

class Complex {
private:
    double real;    // 实部
    double imag;    // 虚部
public:
    Complex(double r = 0, double i = 0): real(r), imag(i) {}    // 构造函数
    Complex operator+(Complex &c);    // 加法重载
    Complex operator-(Complex &c);    // 减法重载
    Complex operator*(Complex &c);    // 乘法重载
    void print();    // 输出函数
};

Complex Complex::operator+(Complex &c) {
    Complex temp(real + c.real, imag + c.imag);
    return temp;
}

Complex Complex::operator-(Complex &c) {
    Complex temp(real - c.real, imag - c.imag);
    return temp;
}

Complex Complex::operator*(Complex &c) {
    Complex temp(real * c.real - imag * c.imag, real * c.imag + imag * c.real);
    return temp;
}

void Complex::print() {
    cout << "(" << real << ", " << imag << "i)" << endl;
}

int main() {
    Complex c1(1, 2), c2(3, 4), c3, c4, c5;
    c3 = c1 + c2;
    c4 = c1 - c2;
    c5 = c1 * c2;
    cout << "c1 = ";
    c1.print();
    cout << "c2 = ";
    c2.print();
    cout << "c1 + c2 = ";
    c3.print();
    cout << "c1 - c2 = ";
    c4.print();
    cout << "c1 * c2 = ";
    c5.print();
    return 0;
}

输出结果为：

c1 = (1, 2i)
c2 = (3, 4i)
c1 + c2 = (4, 6i)
c1 - c2 = (-2, -2i)
c1 * c2 = (-5, 10i)

其中，`operator+`、`operator-`、`operator*` 分别重载了加法、减法、乘法运算符。这些运算符重载函数都是作为 Complex 类的成员函数实现的。在 main 函数里，我们创建了三个 Complex 类的对象，分别进行加、减、乘运算，并输出结果。