Finding bug in simple add function

Question

This was asked in an interview. "There is a bug in the below function, what is it?". It is simple add c function and main function calls it. Given some clue -- "Give different set of input values, test and find bug".

int add (int x, int y)
{ 
    return x + y;
}

Answer 1

The problem can be integer overflow occurs if x+y is greater than INT_MAX or less than INT_MIN. So use long long as return type.