/* File: allocate3.c

   This file demonstrates memory allocation,
   where the size of the array grows.
*/

#define STARTING_SIZE 10
#define SENTINNEL -1

#include <stdio.h>
#include "genlib.h"
#include "simpio.h"
#include <malloc.h>

main() {
   int i, j, size, n, array_size,  *A, *New, *temp;

   /* get a block of memory for size integer */
   A = malloc( STARTING_SIZE * sizeof(int) ) ;
   if (A == NULL) {
      Error("Oops, we're out of memory\n") ;
   }
   array_size = STARTING_SIZE ;

   printf("Enter the elements of the integer array.\n") ;
   printf("Use -1 to indicate the end of the array.\n") ;

   /* Read in the integer array */
   i = 0 ;
   while(TRUE) {
      n = GetInteger() ;
      if (n == SENTINNEL) break ;

      /* Check if we have enough space */
      if (i == array_size) {
	 array_size = 2 * array_size ;
	 New = malloc(array_size * sizeof(int)) ;

	 if (New == NULL) Error("Memory capacity exceeded\n") ;

	 /* Copy old array into new array */
	 for (j = 0 ; j < i ; j++) {
             New[j] = A[j] ;
	 }

	 /* Make A point to new array, free old array */ 
         temp = A ; 
	 A = New ;
	 free(temp) ;
      }

      A[i] = n ;
      i++ ;
   }
   size = i ;

   /* Print out contents of the array */
   printf("\nThe integers in array A\n") ;
   for (i = 0 ; i < size ; i++) {
      printf("A[%d] = %d\n", i, A[i]) ;
   }

   /* Give up use of the memory block */
   free(A) ;
}