复数相减虚部为负数怎么办，求解啊

#include

#include

using namespace std;

class Complex{

public:

Complex(double r=0,double i=0);

Complex operator +(const Complex& c);

Complex operator -(const Complex& c);

void print() const;

private:

double real,imag;

};

Complex::Complex(double r , double i){

real=r;

imag=i;

}

Complex Complex::operator +(const Complex& c){

double r=real+c.real;

double i=imag+c.imag;

return Complex(r,i);

}

Complex Complex::operator -(const Complex& c){

double r=real-c.real;

double i=imag-c.imag;

return Complex(r,i);

}

void Complex::print() const{
cout<<real<<'+'<<imag<<'i'<<endl;
}
int main()
{
double r, i;
cin >> r >> i;
Complex c(r, i);
cin >> r >> i;
Complex n(r, i);
Complex c1=c+n;
Complex c2=c-n;
c1.print();
c2.print();
return 0;
}

#include <iomanip>

// ...

void Complex::print() const
{
    const double eps = 1e-6;
    if (abs(imag) < eps)
    {
        cout << noshowpos << real;
    }
    else
    {
        if (abs(real) < eps)
            cout << noshowpos << imag << 'i';
        else
            cout << noshowpos << real << showpos << imag << 'i';
    }
    cout << '\n';
}