If i have a class: Code: class Rational{ .. .. Rational operator+(Rational &rat); friend Rational operator+(Rational rat1, Rational rat2); ... ... }; Rational operator+(Rational rat1, Rational rat2); int main() { Rational r1(2,3),r2(4,5); .... ... r1=r1+r2; ... } ------------------------------- I know in this case the member function of class Rational will be invoked. But how do i invoke the non-member friend function which is in the global area. Am i supposed to do this: r1=operator+(r1,r2); ?

Normally, you would have operator += as the member function (returning a reference), and operator + as the non member function (implemented in terms of the member +=). And no need for the non-member function to be a friend. Code: class Rational { public: Rational & operator += (const Rational & rat) { // code then return *this; } }; Rational operator + (Rational rat1, const Rational & rat2) { return rat1+=rat2; } // or Rational operator + (const Rational & rat1, const Rational & rat2) { Rational tmp = rat1; return tmp+=rat2; }