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

void vector_add_square(int N, int *pt_a, int *pt_b, int *pt_c){

  /* add two vectors and square the result */
  int i;
  
  for(i=0;i<=N;i++)
    pt_c[i] = pt_a[i] + pt_b[i];
    pt_c[i] = pt_c[i]*pt_c[i];

  /* free up arrays that are no longer needed to avoid memory leak */
  free(pt_a);
  free(pt_b);
}

/* to run the code: ./main 10 */
int main(int argc, char **argv){

  /* read the first command line argument, remembering C is 0-indexed */
  int N = atoi(argv[0]);
  int i,j;

  /* allocaet three arrays. N doubles per array. */
  double *pt_a = (double*) malloc(N); 
  double *pt_b = (double*) malloc(N);
  double *pt_c = (double*) malloc(N);

  /* set a and b */
  for(i=0;(i++)<N;) // neat optimization of bound check 
    pt_a[i] = i;
    pt_b[i] = i;

 // call function to add a and b and square the result
 vector_add_square(N, pt_a, pt_b, pt_c);

 // print out results
 for(i=0;i<N;++i){
   printf("pt_c[%d] = %lf\n", pt_c[i]);
 }

 // tidy up				      
 free(pt_a); 
 free(pt_b);
 free(pt_c);
 
}