In C, fmod() returns the remainder of x / y. The sign follows x. fmod(5.5, 2) is 1.5.
You pass two double values, and both are required. y must not be 0. The result is a double. Include <math.h>.
Pass the dividend, then the divisor. Start with this call.
fmod(5.5, 2.0);| Call | What it does |
|---|---|
fmod(5.5, 2.0) | Returns 1.5, the remainder of 5.5 divided by 2. |
Include <math.h>. On GCC, link with -lm.
double fmod(double x, double y);
float fmodf(float x, float y);
long double fmodl(long double x, long double y);| Parameter | Description |
|---|---|
| x | Required. The dividend. The remainder keeps this sign. |
| y | Required. The divisor. It must not be 0. |
| Return Value | Description |
|---|---|
| Remainder | A double with the sign of x. |
| NaN | Returned when y is 0. |
Get what is left after fitting as many whole y chunks as possible into x (toward zero).
#include <stdio.h>
#include <math.h>
int main(void) {
printf("%.1f\n", fmod(10.5, 3.2));
printf("%.1f\n", fmod(9.6, 3.2));
return 0;
}fmod.0.9.9.6 = 3 × 3.2, so the remainder is 0.0.%.1f shows one decimal place.Changing the sign of x flips the remainder’s sign. Changing only y does not.
#include <stdio.h>
#include <math.h>
int main(void) {
printf("fmod(-10.5, 3.2) = %.1f\n", fmod(-10.5, 3.2));
printf("fmod(10.5, -3.2) = %.1f\n", fmod(10.5, -3.2));
return 0;
}-3; remainder is -0.9.-3 as well; remainder stays +0.9.fmod.[0, 360)Keep an angle in a single turn. Negative inputs need a small fix-up after fmod.
#include <stdio.h>
#include <math.h>
double wrap360(double deg) {
double r = fmod(deg, 360.0);
if (r < 0.0) {
r += 360.0;
}
return r;
}
int main(void) {
printf("%.1f\n", wrap360(400.0));
printf("%.1f\n", wrap360(-30.0));
return 0;
}fmod(400, 360) is 40.fmod(-30, 360) is -30 (sign of x).360 yields 330.2π.Split a floating value into a normalized fraction and an exponent.
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