This error never appeared before, I don't understand why it is happening. I am creating a C program to create an array and then realloc it to add more elements. Im applying many unecessary concepts in the same program to condense some knowledge.

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

  // ALWAYS when doing a definition of new elements in a arrays, NEVER use size as a parameter
  // because if you assign one element as one, it will reset the value of size then reseting 
  // size < sizenew.
  // Ex: Do not do:
  //
  // for (size; size < newsize; size  ) scanf ("%hu", &size)
  //
  // the number you choose for scanf will affect the number of times the loop will do, because size
  // is a parameter of while 
 

int main()
{
  _Bool decision;
  int* array;
  unsigned short size, newelements, oldsize, add, minus_oldsize, newsize, i, j;

  printf("Hello! put the size of the initial int array!\n");
  scanf("%hu", &size);
  
  array = malloc(size * 4);

  printf("Put the array elements one by one\n");
  for (i = 0; i < size; i  ) scanf("%d", array   i);

  printf("This is your array:\n");
  for (j = 0; j < size; j  ) printf("%d\n", *(array   j));

  printf("Do you want to add more elements? no(0) yes(1)\n");
  scanf("%d", &decision);
  if (decision != 1) return -1;

  printf("How many elements you want to add?\n");
  scanf("%d", &newelements);
  newsize = size   newelements;

  array = realloc(array, newsize * 4);

  free(array);
  
  return 0;
}

error: realloc(): invalid pointer

CodePudding user response：

It seems the problem is this call of scanf for an object of the type _Bool

_Bool decision;

//...

scanf("%d", &decision);

Unfortunately there is no conversion specifier for objects of the type _Bool that can be safely used in a call of scanf.

Instead you could use an object of the type int.

Another problem is using an incorrect conversion specifier in this call

scanf("%d", &newelements);

It seems you mean

scanf("%hu", &newelements);