Question

What is a pointer to pointer in C

Answer 1

/*
Pointer to pointer (**pp) is a pointer variable which holds the address 
of another pointer variable (*p).
*/
 
#include <stdio.h>
 
int main(void)
{
    int n = 13, *p = &n, **pp = &p;
     
    printf("n    = %d (n)\n", n);
    printf("*p   = %d (*p = &n)\n", *p);
    printf("**pp = %d (**pp = &p)\n\n", **pp);
     
    printf("&n  = %p (n)\n", &n);
    printf("p   = %p (*p = &n)\n", p);
    printf("*pp = %p (**pp = &p)\n\n", *pp);
 
    printf("&p  = %p\n", &p);
    printf("pp  = %p (**pp = &p)\n\n", pp);
 
    printf("&pp = %p\n", &pp);
 
    return 0;
}
 


   
/*
run:
     
n    = 13 (n)
*p   = 13 (*p = &n)
**pp = 13 (**pp = &p)

&n  = 0x7ffcbff9f444 (n)
p   = 0x7ffcbff9f444 (*p = &n)
*pp = 0x7ffcbff9f444 (**pp = &p)

&p  = 0x7ffcbff9f448
pp  = 0x7ffcbff9f448 (**pp = &p)

&pp = 0x7ffcbff9f450
 
*/

 

 

70+ SQL courses for beginners and professionals