Operators defined only one way - C++

Question

I've created a class of complex numbers, defined operations and some functions like arg, modulus etc. I've also defined the imaginary unit i as constant in a namespace. The problem is that z = i + 2 doesn't return any error and work correctly but the compiler doesn't accept the line z = 2 + i saying that the operand is invalid between int and const complex.

What should I do to get the operation defined both ways?

Answer 1

You should implement either a conversion between integer and complex number or define both operators:

complex operator+(int a, const complex& b)

and

complex operator+(const complex& a, int b)

Answer 2

You should overload complex operator+(int lhs, const complex& rhs); for your class. Make this a friend function so you pass in both parameters.