Dynamic Memory Allocation in C

-

Dynamic Memory Allocation in C

Introduction

In C programming, memory can be allocated in two ways:

  • Static (compile-time)
  • Dynamic (run-time)

👉 Dynamic Memory Allocation (DMA) allows memory to be allocated during program execution.

What is Dynamic Memory Allocation?

DMA is:
👉 Allocating memory at runtime using functions

Why Use DMA?

  • ✔ Efficient memory usage
  • ✔ Allocate memory as needed
  • ✔ Handle large data
  • ✔ Flexible programming

Header File

#include <stdlib.h>

Dynamic Memory Functions

  • malloc()
  • calloc()
  • realloc()
  • free()

1. malloc()

👉 Allocates memory (uninitialized)

#include <stdio.h>
#include <stdlib.h>

int main() {
    int *ptr;

    ptr = (int*) malloc(5 * sizeof(int));

    if (ptr == NULL) {
        printf("Memory not allocated");
        return 0;
    }

    ptr[0] = 10;
    ptr[1] = 20;

    printf("%d %d", ptr[0], ptr[1]);

    free(ptr);

    return 0;
}

Output

10 20

2. calloc()

👉 Allocates memory and initializes to 0

#include <stdio.h>
#include <stdlib.h>

int main() {
    int *ptr;

    ptr = (int*) calloc(3, sizeof(int));

    for (int i = 0; i < 3; i++) {
        printf("%d ", ptr[i]);
    }

    free(ptr);

    return 0;
}

Output

0 0 0

3. realloc()

👉 Resizes allocated memory

#include <stdio.h>
#include <stdlib.h>

int main() {
    int *ptr;

    ptr = (int*) malloc(2 * sizeof(int));

    ptr[0] = 5;
    ptr[1] = 10;

    ptr = (int*) realloc(ptr, 4 * sizeof(int));

    ptr[2] = 15;
    ptr[3] = 20;

    for (int i = 0; i < 4; i++) {
        printf("%d ", ptr[i]);
    }

    free(ptr);

    return 0;
}

Output

5 10 15 20

4. free()

👉 Deallocates memory

free(ptr);

👉 Prevents memory leaks

DMA Functions Table

Function Purpose
malloc() Allocate memory
calloc() Allocate & initialize
realloc() Resize memory
free() Deallocate memory

Important Notes

  • Always check for NULL
  • Free memory after use
  • Avoid memory leaks
  • Use correct size

Common Mistakes

  • ❌ Not freeing memory
  • ❌ Using uninitialized memory
  • ❌ Wrong size allocation
  • ❌ Memory leaks

Pro Tips

  • ✔ Always use free()
  • ✔ Check pointer before use
  • ✔ Use calloc() when needed
  • ✔ Practice dynamic arrays

Conclusion

Dynamic Memory Allocation allows flexible and efficient memory usage in C programming. It is essential for advanced applications.

Master DMA to handle memory effectively.

👉 This article is part of Dharani Tech Edu Hub — where learning programming is made simple and practical.

Location: Kanjikoil, Tamil Nadu 638116, India

Comments

Post a Comment

Popular posts from this blog

Introduction to C Programming

-
Dharani Tech Edu Hub Introduction to C Programming Introduction Programming is the way we communicate with computers to perform tasks. Among all programming languages, C programming is one of the most powerful and widely used languages. If you are just starting your coding journey, C is the perfect place to begin. It builds a strong foundation and helps you understand how programs actually work behind the scenes. What is C Programming? C is a general-purpose programming language developed by Dennis Ritchie in 1972 at Bell Labs. It is mainly used for: System programming Operating systems Embedded systems Application development 👉 In simple words: C is a language that helps you write instructions for a computer to follow. Why Should You Learn C? Here are some important reasons: Foundation for other languages (C++, Java, Python are based on C concepts) Fast and efficient Used in performance-critical applications Low-level access Helps understand memo...
Read more

Operators in C

-
Dharani Tech Edu Hub Operators in C Introduction In C programming, operators are used to perform operations on variables and values. They are essential for performing calculations, comparisons, and logical decisions in programs. 👉 In simple terms: Operators are symbols that perform operations on operands (values). What are Operators? An operator is a symbol that tells the compiler to perform a specific operation. 👉 Example: int a = 10 + 5 ; Here: + → operator 10 and 5 → operands Types of Operators in C C provides several types of operators: Arithmetic Operators Relational Operators Logical Operators Assignment Operators Increment & Decrement Operators Bitwise Operators Conditional (Ternary) Operator Special Operators 1. Arithmetic Operators Used for mathematical calculations: Operator Description Example + Addition a + b - Subtraction a - b * Multiplica...
Read more

Input & Output in C

-
Dharani Tech Edu Hub Input & Output in C Introduction In any programming language, interacting with the user is very important. This is done using Input and Output operations . Output → Displaying data to the user Input → Taking data from the user In C, we mainly use: printf() → for output scanf() → for input Header File Required To use input and output functions, include: #include <stdio.h> printf() Function printf() is used to display output on the screen. Syntax printf ( "message" ); Example #include <stdio.h> int main () { printf ( "Welcome to Dharani Tech Edu Hub!" ); return 0 ; } Output Welcome to Dharani Tech Edu Hub! Using Variables with printf() #include <stdio.h> int main () { int age = 20 ; printf ( "Age = %d" , age ); return 0 ; } Output Age = 20 Format Specifiers Used to display different data types: Data Type Format Specifier ...
Read more