calloc function - Mini Project: Build & Apply

Using calloc to Allocate Memory in C

📖 Scenario: You are writing a simple C program to store the ages of 5 people. You want to allocate memory dynamically for an array of 5 integers and initialize all values to zero.

🎯 Goal: Learn how to use the calloc function to allocate and initialize memory for an integer array, then print the values.

📋 What You'll Learn

Create a pointer variable to hold the address of the allocated memory.

Use calloc to allocate memory for 5 integers.

Check if the memory allocation was successful.

Print the values stored in the allocated memory to confirm they are zero.

Free the allocated memory at the end.

💡 Why This Matters

🌍 Real World

Dynamic memory allocation is used in programs where the amount of data is not known before running, such as reading user input or handling large datasets.

💼 Career

Understanding <code>calloc</code> and memory management is essential for C programmers working in systems programming, embedded systems, or performance-critical applications.

1

Declare a pointer for integer array

Declare a pointer variable called ages of type int * to hold the address of the allocated memory.

C

// Declare an integer pointer called ages
// Your code here

Need a hint?

Use int *ages; to declare a pointer to integers.

2

Allocate memory using calloc

Use calloc to allocate memory for 5 integers and assign it to ages. Include #include <stdlib.h> at the top if not already present.

C

int *ages;
// Allocate memory for 5 integers using calloc
// Your code here

Need a hint?

Use calloc(5, sizeof(int)) to allocate memory for 5 integers initialized to zero.

3

Check allocation and print values

Write an if statement to check if ages is not NULL. Then use a for loop with variable i from 0 to 4 to print each value in ages[i].

C

#include 

int *ages;
ages = calloc(5, sizeof(int));

// Check if allocation succeeded and print values
// Your code here

Need a hint?

Use if (ages != NULL) to check allocation. Use a for loop to print each element.

4

Free the allocated memory

Add a line to free the memory pointed to by ages using the free function after printing the values.

C

#include 
#include 

int *ages;
ages = calloc(5, sizeof(int));

if (ages != NULL) {
    for (int i = 0; i < 5; i++) {
        printf("ages[%d] = %d\n", i, ages[i]);
    }
}
// Free the allocated memory
// Your code here

Need a hint?

Use free(ages); to release the memory after use.