Introduction to Pointers

Pointers are variables that store memory addresses instead of actual values.

In this lesson, you will learn:

• What pointers are and how they work.
• How to declare and initialize pointers.
• How to use pointers to access memory.

Declaring a Pointer

A pointer is declared using the * operator.

Example:

int *ptr;

This creates a pointer variable ptr that can store the address of an integer.

Getting Memory Address

The & operator is used to get the memory address of a variable.

Example:

int num = 10; int *ptr = #

Here, ptr stores the address of num.

Dereferencing a Pointer

The * operator is used to access the value stored at a pointer's memory address.

Example:

int value = *ptr;

This retrieves the value stored at the memory address held by ptr.

Example: Using Pointers

This program demonstrates pointer declaration, initialization, and dereferencing.

#include <stdio.h>

int main() {
    int num = 42;
    int *ptr = &num;
    printf("Value of num: %d\n", num);
    printf("Memory address of num: %p\n", ptr);
    printf("Value accessed through pointer: %d\n", *ptr);
    return 0;
}

Pointer Arithmetic

Pointers can be used in arithmetic operations.

Example:

ptr++;

This moves the pointer to the next memory location.

Example: Pointer Arithmetic

This program demonstrates pointer arithmetic.

#include <stdio.h>

int main() {
    int arr[3] = {10, 20, 30};
    int *ptr = arr;
    printf("First element: %d\n", *ptr);
    ptr++;
    printf("Second element: %d\n", *ptr);
    return 0;
}

Advantages of Pointers

Pointers are useful for:

• Efficient memory management.
• Dynamic memory allocation.
• Optimized data structures (linked lists, trees).

Summary

In this lesson, you learned:

• How to declare and use pointers.
• How to access memory addresses and values.
• How to perform pointer arithmetic.

Next, we will explore dynamic memory allocation in C!