Recursive Calculation of the Exponential Function in C

e(x)=1+ x/1! + x^2/2! + x^3/3! + ... + x^n/n! with  x^n/n! <   Ɛ

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

unsigned long fact_recursive (unsigned short nombre)
{
    if (number == 0)
        return 1;
    else
        return number * fact_recursive(number - 1);
}

unsigned int puiss(long int x, int n)
{
  if(n == 0)
    return 1;
  if(n == 1)
    return x;
  int x2 = powers(x,n/2);
  if(n%2 == 0)
    return x2*x2;
  return x2 * x2 * x;
}

double calcul_formule(int x, int n, int epsilon)
{
      double fraction = (double)puiss(x,n) / (double)fact_recursive(n);
      if(n==0)
      {
              return 1;
     }
      else{
          //Verification of the condition if powers(x,n)/n! > epsilon
          if(fraction < epsilon)
              return fraction+calcul_formule(x,n-1,epsilon);
          else
              return calcul_formule(x,n-1,epsilon);
     }

}

int main(int argc, char *argv[])
{
      int x,n,epsilon;
      printf("Enter the value of x: ");
      scanf("%d",& x);
      printf("Enter the value of n: ");
      scanf("%d",& n);
      printf( Enter the value of Epsilon: ");
      scanf("%d",& epsilon);
      //calculation of the formula
      printf("exp( %d ) = %f\n",x,calcul_formule(x,n,epsilon) );
      system("pause");
}