Question

I am facing a problem with the code below which is run on Visual Studio 2008. How do I write the function definition for operator + when you have a statement to be overloaded as follows?

class Distance
{
    private:
        int feet,inches;
};

main......

Distance Obj, Obj1(2, 2);

Obj = 3 + Obj1; // This line here

Obj1+3 is easy, but how does this one compiler know that it has to do overloading?

Suppose I have to add the value 3 to the data member feet of Obj1.

Answer 1

Generally an operator of that form would be declared as:

Distance operator+(int lhs, const Distance& rhs) {
  // Assuming the int value represents feet
  return Distance(rhs.feet + lhs, rhs.inches);
}

You’d probably also want to define the symmetric:

Distance operator+(const Distance& lhs, int rhs) {
  // Assuming the int value represents feet
  return Distance(lhs.feet + rhs, lhs.inches);
}

Also, I suggest you heed the advice of James McNellis–your job will be simplified if you just have one member representing lengths in a single unit.