How to Efficiently Round Up to the Nearest Multiple in C ?

int roundUp(int numToRound, int multiple)<br>{</p>
<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false">if (multiple == 0)
    return numToRound;

int remainder = numToRound % multiple;
if (remainder == 0)
    return numToRound;

return numToRound + multiple - remainder;

}

This method utilizes basic integer arithmetic to calculate the nearest multiple for positive numbers. It is straightforward and works efficiently.

Handling Negative Numbers

When rounding negative numbers, the definition of "up" becomes ambiguous. Depending on the specific application, different interpretations of rounding up may be appropriate. The provided solution assumes rounding up means a result that is always greater than or equal to the input number:

int roundUp(int numToRound, int multiple)<br>{</p>
<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false">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;