Pointers

Lesson 27
Author : Afrixi
Last Updated : January, 2023

C - Programming Language

This course covers the basics of programming in C.

In C, a pointer is a variable that stores the memory address of another variable. Pointers are used to manipulate and access memory directly in C. Here is an example of how pointers work:

#include <stdio.h>

int main() {
  int var = 10;     // define an integer variable called var with value 10
  int *ptr = &var;  // define a pointer variable called ptr that points to the address of var

  printf("var value: %d\n", var);   // print the value of var
  printf("var address: %p\n", &var);// print the memory address of var
  printf("ptr value: %p\n", ptr);   // print the value of ptr
  printf("ptr points to: %d\n", *ptr);// print the value stored at the memory address pointed to by ptr

  return 0;
}

In this example, we define an integer variable called var and initialize it with the value 10. Then, we define a pointer variable called ptr using the * symbol to indicate that it is a pointer to an integer. We set the value of ptr to the memory address of var using the & operator.

We then use printf statements to print out the value of var, the memory address of var, the value of ptr, and the value stored at the memory address pointed to by ptr. The last printf statement uses the * symbol to dereference the pointer and access the value stored at the memory address it points to.

Output:

var value: 10
var address: 0x7fff5fbff5d4
ptr value: 0x7fff5fbff5d4
ptr points to: 10

As you can see, the value of var is 10, its memory address is 0x7fff5fbff5d4, and the value of ptr is the same memory address. We then use the * symbol to dereference the pointer and access the value stored at the memory address it points to, which is 10.

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