Question

How to use pointer to pointer in C

Answer 1

#include <stdio.h>

int main(int argc, char **argv)
{
    int n = 7, *p = &n, **pp = &p;
	
	printf("%d\n", n);
	printf("%d\n", *p);
	printf("%d\n", **pp);
	
    return 0;
}


/*
run:

7
7
7

*/

 

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Answer 2

#include <stdio.h>

int main(int argc, char **argv)
{
    int n = 7, *p = &n, **pp = &p;
	
	printf("%d\n", n);
	printf("%d\n", *p);
	printf("%d\n", **pp);
	
	// address of n
	printf("%p\n", &n);
	printf("%p\n", p);
	printf("%p\n", *pp);
	
    return 0;
}


/*
run:

7
7
7
000000000062FE44
000000000062FE44
000000000062FE44

*/

 

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Answer 3

#include <stdio.h>

int main() {
    int n = 99;
    int *p;
    int **pp;

    p = &n;
    pp = &p;

    printf("n = %d\n", n);
    printf("*p = %d\n", *p);
    printf("**pp = %d\n", **pp);

    return 0;
}



/*
run:

n = 99
*p = 99
**pp = 99

*/

 

Cleaner teeth, healthier you!
Get The Secret to a Bright and Healthy Smile