C言語では、trunc()は切り捨て関数、truncf()は切り捨て関数(単精度)、truncl()は切り捨て関数(長倍精度)を表します。

double trunc(double argument)

#include <stdio.h>
#include <math.h>
main() {
   double a, b, x, y;
   x = 53.26;
   y = 75.86;
   a = trunc(x);
   b = trunc(y);
   printf("The value of a: %lf</p><p>",a);
   printf("The value of a: %lf</p><p>",b);
}

float tuncf(float argument)

#include <stdio.h>
#include <math.h>
main() {
   float a, b, x, y;
   x = 53.26;
   y = 75.86;
   a = truncf(x);
   b = truncf(y);
   printf("The value of a: %f</p><p>",a);
   printf("The value of a: %f</p><p>",b);
}

long double truncl(long double argument)

#include <stdio.h>
#include <math.h>
main() {
   long double a, b, x, y;
   x = 53547.55555555555;
   y = 78547.55555555523;
   a = truncl(x);
   b = truncl(y);
   printf("The value of a: %Lf</p><p>",a);
   printf("The value of a: %Lf</p><p>",b);
}

The value of a: 53547.000000
The value of a: 78547.000000