Rounding up to the nearest multiple of a number
algorithm, c++, rounding
Solution
This works for positive numbers, not sure about negative. It only uses integer math.
int roundUp(int numToRound, int multiple)
{
if (multiple == 0)
return numToRound;
int remainder = numToRound % multiple;
if (remainder == 0)
return numToRound;
return numToRound + multiple - remainder;
}
Edit: Here's a version that works with negative numbers, if by "up" you mean a result that's always >= the input.
int roundUp(int numToRound, int multiple)
{
if (multiple == 0)
return numToRound;
int remainder = abs(numToRound) % multiple;
if (remainder == 0)
return numToRound;
if (numToRound < 0)
return -(abs(numToRound) - remainder);
else
return numToRound + multiple - remainder;
}
Problem
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 ```