#include<stdio.h>
#include<stdlib.h>

void zero(double* a) {
	*a = 0.0;
}

int main(int argc, char * argv[]) {
	double x=37.5;
  	printf("avant : %f\n", x);
  	zero(&x);
  	printf("après : %f\n", x);
  	return EXIT_SUCCESS;
}