Pointer to Pointer in C - Pointer to Pointer (Double Pointer)
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Pointer to Pointer (Double Pointer)
- A pointer points to a location in memory and used to store address of variables. So, when we define a pointer to pointer. The first pointer is used to store the address of second pointer ie. Called as double pointers.
How to declare a pointer to pointer in C ?
- Declaring Pointer to Pointer is similar to declaring pointer in C. The difference is to place an additional ‘*’ before the name of pointer.
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Syntax
int **ptr; // declaring double pointers
Sample Code
#include <stdio.h>
int main()
{
int a=10; //normal variable
int *ptr_a;//pointer variable
ptr_a = &a;
int **ptr_ptra; //pointer to pointer
ptr_ptra = &ptr_a;
printf("Value of a: %d\n",a);
printf("Value of a using pointer: %d\n",*ptr_a);
printf("Value of pointer to pointer: %d\n",**ptr_ptra);
return 0;
}
Output
Value of a: 10
Value of a using pointer: 10
Value of pointer to pointer: 10