rounding - How to round floating point numbers to the nearest integer in C?

Question

Is there any way to round numbers in C?

I do not want to use ceil and floor. Is there any other alternative?

I came across this code snippet when I Googled for the answer:

(int)(num < 0 ? (num - 0.5) : (num + 0.5))

The above line always prints the value as 4 even when float num =4.9.

Answer 1

4.9 + 0.5 is 5.4, which cannot possibly round to 4 unless your compiler is seriously broken.

I just confirmed that the Googled code gives the correct answer for 4.9.

marcelo@macbookpro-1:~$ cat round.c 
#include <stdio.h>

int main() {
    float num = 4.9;
    int n = (int)(num < 0 ? (num - 0.5) : (num + 0.5));
    printf("%d
", n);
}
marcelo@macbookpro-1:~$ make round && ./round
cc     round.c   -o round
5
marcelo@macbookpro-1:~$