#include <stdio.h>
#include <math.h>

float floatMod(float a, float b)
{
    return a - (round(a / b) * b);
}

int main()
{
    printf("%f\n", fmodf(18.5f, 4.2f));
    printf("%f\n", floatMod(18.5f, 4.2f));

	printf("%f\n", fmodf(-18.5f, 4.2f));
    printf("%f\n", floatMod(-18.5f, 4.2f));

}