/* Code designed to test random reads and writes to a large array */

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

int main ( int argc, char *argv[] )
{
  int *p;
  int i, val, temp, length;
  
  if ( argc != 2 ) /* There should be one argument for correct execution */
    {
      /* We print argv[0] assuming it is the program name */
      printf( "usage: %s length\n", argv[0] );
      exit ( EXIT_FAILURE );
    }
  else
    {
      length = (int)strtol (argv[1], NULL, 10 );
    }
  

  // We use calloc now so we can read as well as write.
  p = calloc(length, sizeof(int));
  
  
  srand(time(NULL));
  
  // We make a read and a write to each randomly chosen position in the array
  for (i=0;i<length;i++) {   
    val = rand() % length;
    temp +=  p[val];
    p[val] = i;
 }
  
  return temp;
}