Memory allocation flow - Mini Project: Build & Apply

Memory allocation flow

📖 Scenario: Imagine you are managing a small library of books in a computer program. You want to keep track of how many books you have and store their titles. Since the number of books can change, you need to allocate memory dynamically.

🎯 Goal: You will write a C program that dynamically allocates memory to store book titles, updates the number of books, and then prints the stored titles.

📋 What You'll Learn

Create a pointer to hold dynamically allocated memory for book titles

Create a variable to store the number of books

Use malloc to allocate memory for 3 book titles

Store 3 book titles in the allocated memory

Print all stored book titles

💡 Why This Matters

🌍 Real World

Dynamic memory allocation is essential when the amount of data is not fixed, such as storing user inputs or managing collections that grow or shrink.

💼 Career

Understanding memory allocation helps in writing efficient C programs, debugging memory issues, and is crucial for systems programming and embedded development.

1

Create a pointer and a variable for books

Declare a pointer called books of type char ** to hold book titles. Also declare an integer variable called num_books and set it to 3.

C

# Declare a pointer called books and an integer num_books
# Your code here

Need a hint?

Use char **books; to hold an array of strings and int num_books = 3; to store the count.

2

Allocate memory for book titles

Use malloc to allocate memory for num_books pointers to char and assign it to books.

C

char **books;
int num_books = 3;

# Allocate memory for books
# Your code here

Need a hint?

Use malloc(num_books * sizeof(char *)) to allocate memory for the array of pointers.

3

Store book titles in allocated memory

Use malloc to allocate memory for each book title (assume max 20 characters). Then copy these exact titles into books[0], books[1], and books[2]: "C Programming", "Data Structures", "Algorithms".

C

char **books;
int num_books = 3;

books = (char **)malloc(num_books * sizeof(char *));

# Allocate memory for each book title and copy the titles
# Your code here

Need a hint?

Use malloc(20 * sizeof(char)) for each title and strcpy to copy the exact strings.

4

Print all stored book titles

Use a for loop with variable i from 0 to num_books - 1 to print each book title stored in books[i].

C

char **books;
int num_books = 3;

books = (char **)malloc(num_books * sizeof(char *));

books[0] = (char *)malloc(20 * sizeof(char));
strcpy(books[0], "C Programming");

books[1] = (char *)malloc(20 * sizeof(char));
strcpy(books[1], "Data Structures");

books[2] = (char *)malloc(20 * sizeof(char));
strcpy(books[2], "Algorithms");

# Print all book titles
# Your code here

Need a hint?

Use a for loop from 0 to num_books - 1 and printf to print each title.