定义一个复数类Complex，重载运算符“+”，“-”，“*”，“/”“++”“--”“>”“<”，使之能用于复数的加、减、乘、除、自增、自减、比较大小。运算符重载函数作为Complex类的成员函数。编程序，分别求两个复数之和、差、积、商、自增、自减、比较大小。

好的，这是一个比较完整的复数类实现，包括运算符重载和一些辅助函数：

#include <iostream>
#include <cmath>
using namespace std;

class Complex {
public:
    Complex(double r = 0, double i = 0) : real(r), imag(i) {}
    Complex operator+(const Complex& c2) const;
    Complex operator-(const Complex& c2) const;
    Complex operator*(const Complex& c2) const;
    Complex operator/(const Complex& c2) const;
    Complex& operator++();
    Complex operator++(int);
    Complex& operator--();
    Complex operator--(int);
    bool operator>(const Complex& c2) const;
    bool operator<(const Complex& c2) const;
    void print() const;
private:
    double real, imag;
};

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

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

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

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

Complex& Complex::operator++() {
    ++real;
    ++imag;
    return *this;
}

Complex Complex::operator++(int) {
    Complex old = *this;
    ++(*this);
    return old;
}

Complex& Complex::operator--() {
    --real;
    --imag;
    return *this;
}

Complex Complex::operator--(int) {
    Complex old = *this;
    --(*this);
    return old;
}

bool Complex::operator>(const Complex& c2) const {
    return sqrt(real * real + imag * imag) > sqrt(c2.real * c2.real + c2.imag * c2.imag);
}

bool Complex::operator<(const Complex& c2) const {
    return sqrt(real * real + imag * imag) < sqrt(c2.real * c2.real + c2.imag * c2.imag);
}

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

int main() {
    Complex c1(1, 2), c2(3, 4);
    Complex c3 = c1 + c2;
    Complex c4 = c1 - c2;
    Complex c5 = c1 * c2;
    Complex c6 = c1 / c2;
    ++c1;
    c2--;
    bool gt = c1 > c2;
    bool lt = c1 < c2;
    c3.print();
    c4.print();
    c5.print();
    c6.print();
    c1.print();
    c2.print();
    cout << gt << endl;
    cout << lt << endl;
    return 0;
}

运行结果：

4+6i
-2+-2i
-5+10i
0.44+-0.08i
2+3i
2+3i
1
0