OK - I'm almost embarrassed posting this here (and I will delete if anyone votes to close) as it seems like a basic question.

Is this the correct way to round up to a multiple of a number in C++?

I know there are other questions related to this but I am specficially interested to know what is the best way to do this in C++:

int roundUp(int numToRound, int multiple)
{
 if(multiple == 0)
 {
  return numToRound;
 }

 int roundDown = ( (int) (numToRound) / multiple) * multiple;
 int roundUp = roundDown + multiple; 
 int roundCalc = roundUp;
 return (roundCalc);
}

Update: Sorry I probably didn't make intention clear. Here are some examples:

roundUp(7, 100)
//return 100

roundUp(117, 100)
//return 200

roundUp(477, 100)
//return 500

roundUp(1077, 100)
//return 1100

roundUp(52, 20)
//return 60

roundUp(74, 30)
//return 90