Convert milliseconds to seconds in C

Question

Simple C question, how can I correctly and succintly convert milliseconds to seconds. There are two constraints:

• I've no floating point support in this tiny subset-of-C compiler

• I need the seconds rounded to the nearest second(1-499ms rounds down,500-999ms rounds up. Don't need to care about negative values)

  int mseconds = 1600; // should be converted to 2 seconds
  int msec = 23487;  // should be converted to 23 seconds
  

Answer 1

This should work

int sec = ((msec + 500) / 1000);

Answer 2

int seconds = msec / 1000;
if (msec % 1000 > 500)
    seconds++;