定义一个复数类COMPLEX,重载运算符“+”使之用于复数的加减运算

class complex
{
public:
complex(double r=0,double i=0)
{
real = r;
image = i;
}
double real;
double image;
};
complex operator + (const complex& a,const complex& b)
{
return complex(a.r+b.r,a.i+b.i);
}