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

int main(void) {

  double *a = (double*)malloc(5 * sizeof(double)),
         sum = 0.0;
  int i, j, k;

  if (a == NULL){
    printf("Memory allocation problem. Bye\n");
    exit(EXIT_FAILURE);
  } 

  for (i = 0; i < 5; i++)      /* Initialize a */
    *(a+i) = (double)(i + 1);

  *(a+1) = 2.2;                /* a[1] = 2.2;  */

  for (i = 0; i < 5; i++)
    sum += *(a+i);
  printf("Sum = %f\n", sum);   /* 15.2         */

  free(a);

  return 0;
}