TopCoder - SRM 144 DIV 2 - Time - whatTime

problem statement

In this problem, you have to convert a given second into it's equivalent standard time "h:m:s".
Easily I find how many 3600 are there in it, how many 60 are there left in it, and now I have h, m and s that I have to return a string not integers, so I convert each of them into a string and add them together in one string and return it.

int h = seconds/3600;
int m = (seconds%3600)/60;
int s = seconds%60;

        return f(h) + ":" + f(m) + ":" + f(s);

Function f(int) just converts the given integer into a string like this:
int f( int n )
{
   if( n == 0 )
      return "0";
   string res = "";
   while( n )
   {
      res += n%10 + '0';
      n /= 10;
   }
   reverse( res.begin(), res.end() );
   return res;
}