In the below code, I get memory through malloc and pointed it by pointer ptr. When I assigned value as shown I stored the data in pointer and we know that pointer is located in stack frame.

So my question is: My data(integers) is stored in stack or in heap?

#include<stdio.h>
#include<stdlib.h>
void main()
{
  int *ptr;
  ptr=(int*)malloc(5*sizeof(int));
  ptr[0]=5;
  ptr[1]=6;
  ptr[2]=8;
  ptr[3]=10;
  ptr[4]=11;
}

CodePudding user response：

Yes, the pointer is stored on the stack, but the memory it points to is on the heap. Therefore, the integers are stored on the heap.

CodePudding user response：

Pedantically speaking, from the perspective of the C standard, all the objects involved here simply occupy some memory that is suitably aligned, and disjointed from other objects.

While the notion of a stack and heap are commonplace, the C standard makes no reference to either terms. How and where data is stored is mostly implementation-defined.

The principle thing differentiating them is their visibility and effective lifetimes (see: Storage duration, Lifetime, and Scope):

• The use of ptr is valid until main returns.

• The use of the memory at the address returned by malloc is valid until it is deallocated.

Practically speaking, however, it is generally fair to refer to objects with

• automatic storage duration as existing on the "stack",
• static storage duration as existing in the "data segment", and
• allocated storage duration as existing on the "heap",

as this a very common way C implementations work.

With this terminology, the object designated by the identifier ptr exists on the stack, and the objects accessed via the pointer returned by malloc exist on the heap.