Pointer basics in C.

pointer.c

#include <stdio.h>

/*
Pointers to pointers' pointers. GET YOUR HANDS OFF MY POINTER!!!
A crappy, cheap code snippet by Subsentient.
*/

void main()
{
	int num = 7;
	int num2 = 3;
	int *nump;
	int *numderp;
	//Make a pointer to an integer, yet to be defined.

	int **numpp;
	//Make a pointer to an integer pointer. Double pointer.

	nump = &num; 
	//Give the address of num to the pointer nump, making it act as a second name for num when dereferenced.

	numpp = &nump; 
	//Pointers have addresses too. Give the address of nump to numpp, making numpp a pointer to nump that points to num.

	*numpp = &num2;
	//Dereference numpp with an asterisk, saying "we want to talk to the object pointed to by you, Mr numpp.
	//Next, with the ampersand, we are saying "nump, now you point to num2."

	numderp = nump;
	//This makes our pointer named numderp contain a copy, not just point to, of nump. Dereferencing it would give us num2.

	printf("Direct object reads as %d\n", num);
	printf("Pointer to direct object reads as %d\n", *nump);
	printf("Pointer to the pointer that points to direct object reads as %d\n", **numpp);
	printf("\"Derp\" pointer reads as %d\n", *numderp);
	//Double pointer requires double dereferencing to get to the *final* object actually pointed to.
}