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


/* ------------------------------------------------
   Reduce:

       input:   a[0] a[1] a[2] ...
      output:   a[0] = a[0]  
	 	a[1] = a[0]+a[1]
	 	a[2] = a[0]+a[1]+a[2]
		...
   ------------------------------------------------ */
void reduce(int a[], int n)
{
   int i;

   for (i = 1; i < n; i++)
      a[i] = a[i] + a[i-1];
}


// A utility function ot print an array of size n
void printArray(int a[], int n)
{
   for (int i=0; i < n; i++)
       printf("%d ", a[i]);
   printf("\n");
}



int main (int argc, char *argv[])
{
   int *arr;
   int N;
   int i;

   if (argc < 2)
   {
      printf("Usage error: %s N (N=# elements in array to sort)\n", argv[0]);
      exit(1);
   }

   N = atoi( argv[1] );

   arr = calloc( N, sizeof(int) );

   for ( i = 0 ; i < N; i++ )
      arr[i] = 1;                 // rand()%100;

   printArray(arr, N);


   reduce(arr, N);

   printArray(arr, N);

   return (0);
}