请设计一个复数类Complex，实现以下算法：int main() { Complex a, b, c; cin >> a >> b; c = a + b + 5; cout << c << endl; c = a - b - 5; cout << c << endl; c = a * b * 5; cout << c << endl; c = a / b / 5; cout << c << endl; return 0; }输出分四行，每行是一个复数，用 实部+虚部i 的方式输出，如果虚部是负数，则不要输加号，如果虚部为0，则只输出实部，如果实部为0，则只输出虚部，如果虚部绝对值为1。则只输出i 例如 1+2i 1 1-i 5i

以下是一个实现上述功能的复数类 Complex 的代码：

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

class Complex {
public:
    Complex(double r = 0.0, double i = 0.0) : real(r), imag(i) {}
    friend Complex operator+(const Complex& a, const Complex& b);
    friend Complex operator-(const Complex& a, const Complex& b);
    friend Complex operator*(const Complex& a, const Complex& b);
    friend Complex operator/(const Complex& a, const Complex& b);
    friend istream& operator>>(istream& in, Complex& c);
    friend ostream& operator<<(ostream& out, const Complex& c);
private:
    double real, imag;
};

Complex operator+(const Complex& a, const Complex& b) {
    return Complex(a.real + b.real, a.imag + b.imag);
}

Complex operator-(const Complex& a, const Complex& b) {
    return Complex(a.real - b.real, a.imag - b.imag);
}

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

Complex operator/(const Complex& a, const Complex& b) {
    double divisor = b.real * b.real + b.imag * b.imag;
    return Complex((a.real * b.real + a.imag * b.imag) / divisor, (-a.real * b.imag + a.imag * b.real) / divisor);
}

istream& operator>>(istream& in, Complex& c) {
    in >> c.real >> c.imag;
    return in;
}

ostream& operator<<(ostream& out, const Complex& c) {
    if (c.real == 0 && c.imag == 0) {
        out << 0;
    } else if (c.real == 0) {
        if (c.imag == 1) {
            out << "i";
        } else if (c.imag == -1) {
            out << "-i";
        } else {
            out << c.imag << "i";
        }
    } else if (c.imag == 0) {
        out << c.real;
    } else {
        if (c.imag == 1) {
            out << c.real << "+i";
        } else if (c.imag == -1) {
            out << c.real << "-i";
        } else if (c.imag > 0) {
            out << c.real << "+" << c.imag << "i";
        } else {
            out << c.real << c.imag << "i";
        }
    }
    return out;
}

int main() {
    Complex a, b, c;
    cin >> a >> b;
    c = a + b + 5;
    cout << c << endl;
    c = a - b - 5;
    cout << c << endl;
    c = a * b * 5;
    cout << c << endl;
    c = a / b / 5;
    cout << c << endl;
    return 0;
}

在上述代码中，定义了 Complex 类，包含实部和虚部两个私有成员变量，以及加、减、乘、除等四个公有成员函数，用于实现复数的加减乘除运算；同时还定义了输入输出流的重载操作，用于从标准输入流中读取复数，以及将复数以实部+虚部i 的方式输出。在 main 函数中，定义了三个 Complex 类型的变量 a、b、c，通过 cin 从标准输入流中读入两个复数 a 和 b，然后进行加减乘除运算，并将结果赋值给 c，最后通过 cout 输出结果。