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

int* array_init (int N);
float mean ( int N, int *array );



int main( int argc, char **argv) {

  int *iarray;
  int i;
  int N;
  float ave;


  if ( argc > 1 ){
    N = atoi( argv[1] );
  } else {
    N = 100;
  }

  // create and array with the size of N filled with integer values
  iarray = array_init ( N );

  ave = mean ( N, iarray );


  // print result
  printf(" average value of an array is %f10.4\n", ave );

  // free memory
  free(iarray);

  return 0;

}