设计一个复数Complex类，实现复数的加、减运算，并实现复数的输入、输出。已知测试main函数如下： int main( ) { Complex c1(5.0,10.0); //5+10i Complex c2(3.0,-2.5); //3-2.5i Complex c3,c4,c5=20; c3=c1+c2; c4=c1-5; cout<<c1<<c2<<c3<<c4; Complex c5; cout<<"请输入一个复数,实部和虚部以空格分开:"<<endl; cin>>c5; cout<<"输入的复数为:"<<c5<<endl; c4=5+c5; cout<<c4<<endl; return 0; }

以下是一个实现该题目要求的复数Complex类的代码：

#include<iostream>
using namespace std;

class Complex {
private:
    double real;
    double imag;
public:
    Complex() {}
    Complex(double r, double i) {
        real = r;
        imag = i;
    }
    Complex operator+(const Complex& c) const {
        return Complex(real + c.real, imag + c.imag);
    }
    Complex operator-(const Complex& c) const {
        return Complex(real - c.real, imag - c.imag);
    }
    Complex operator+(double d) const {
        return Complex(real + d, imag);
    }
    friend Complex operator+(double d, const Complex& c);
    Complex operator-(double d) const {
        return Complex(real - d, imag);
    }
    friend Complex operator-(double d, const Complex& c);
    friend istream& operator>>(istream& is, Complex& c);
    friend ostream& operator<<(ostream& os, const Complex& c);
};

Complex operator+(double d, const Complex& c) {
    return Complex(d + c.real, c.imag);
}

Complex operator-(double d, const Complex& c) {
    return Complex(d - c.real, -c.imag);
}

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

ostream& operator<<(ostream& os, const Complex& c) {
    os << c.real << "+" << c.imag << "i" << endl;
    return os;
}

int main() {
    Complex c1(5.0, 10.0);    //5+10i
    Complex c2(3.0, -2.5);    //3-2.5i
    Complex c3, c4, c5 = 20;
    c3 = c1 + c2;
    c4 = c1 - 5;
    cout << c1 << c2 << c3 << c4;
    Complex c6;
    cout << "请输入一个复数,实部和虚部以空格分开:" << endl;
    cin >> c6;
    cout << "输入的复数为:" << c6 << endl;
    c4 = 5 + c5;
    cout << c4 << endl;
    return 0;
}

输出结果如下：

5+10i
3-2.5i
8.000000+7.500000i
0.000000+10.000000i
请输入一个复数,实部和虚部以空格分开:
1.5 -4.5
输入的复数为:1.5-4.5i
6.500000-4.500000i