Question

I have the following code in c++:

    int fff ( int a , int b )
{
   if (a>b )
      return 0;
   else a+b ; 
}

although I didn’t write ‘return’ after else it does not make error ! < br/>
in main() when I wrote:

cout<<fff(1,2);

it printed 1 ?
How did that happened
can any one Explain that ?

Answer 1

This what is called undefined behavior. Anything can happen.

C++ does not require you to always return a value at the end of a function, because it’s possible to write code that never gets there:

int fff ( int a , int b )
{
   if (a>b )
      return 0;
   else return a+b;

   // still no return at end of function
   // syntactically, just as bad as original example
   // semantically, nothing bad can happen
}

However, the compiler cannot determine if you never get to the end of the function, and the most it can do is give a warning. It’s up to you to avoid falling off the end without a return.

And if you do, you might get a random value, or you might crash.