定义一个复数类COMPLEX,重载运算符“+”使之用于复数的加减运算这个函数不能是成员函数和友元函数我想要完整的能直接执行的程序.

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);}