🧠 C Mini Projects for Practice — Dynamic Memory, Structs, Enums & File I/O #

These projects are designed to test and reinforce your understanding of:

• Dynamic Memory Allocation (malloc, calloc, realloc, free)
• Structs and Enums
• Pointers and Arrays
• File I/O (fopen, fprintf, fscanf, etc.)
• Modular Design and Debugging

Each project can typically be completed in 1–2 weeks with good testing and documentation.

More projects available here:
https://github.com/cpro-iiit/snake-project-starter.
https://cs50.harvard.edu/x/2023/labs/4/smiley/.
https://cs50.harvard.edu/x/2023/labs/4/volume/.
https://cs50.harvard.edu/x/2023/labs/5/.
https://cs50.harvard.edu/x/2023/labs/2/.

Reading/understanding these code and adding to it, will give you the confidence for large scale coding.

🚀 Project 1: Student Record Management System #

Description #

Build a program to manage student records (name, roll number, marks, grade, etc.). Support dynamic addition/deletion of students, sorting by marks, and saving/loading from file.

Key Concepts #

• Dynamic arrays of structs
• File I/O (save/load)
• Struct assignment and deep copies

Example Features #

• Add/Delete/Update students
• Calculate class average
• Write to records.txt

🧾 Project 2: Inventory Tracker for a Store #

Description #

Implement a simple inventory system that tracks items, quantities, and prices.

Key Concepts #

• Structs for product info
• File persistence
• Enum for category (ELECTRONICS, FOOD, CLOTHING)

Features #

• Add/Remove items
• Search by name
• Generate invoice file

🧩 Project 3: Library Management System #

Description #

Manage a small digital library database.

Key Concepts #

• Linked list of books (dynamic allocation)
• Struct with nested structs (Book, Author)
• File I/O to store data between runs

Features #

• Add/Remove/Search books
• Issue/Return functionality
• Save state to library.dat

🧮 Project 4: Matrix Operations Toolkit #

Description #

Write a program to handle matrix operations (addition, multiplication, transpose, determinant).

Key Concepts #

• 2D dynamic arrays (pointer to pointer)
• Functions that allocate and free matrices
• Error checking for dimensions

Bonus #

• Include file-based input/output for matrices.

🧠 Project 5: Quiz Game with Leaderboard #

Description #

A text-based quiz game that reads questions from a file, accepts answers, and maintains a leaderboard.

Key Concepts #

• File I/O for question bank and leaderboard
• Struct for player data
• Enum for difficulty level

Features #

• Add questions via file
• Randomize question order
• Save top 5 scores

🧑‍🤝‍🧑 Project 6 — Mini Social Network #

🎯 Goal #

Simulate a simple social network using structs, pointers, and dynamic memory.

🧩 Key Concepts #

• Dynamic memory (malloc, realloc, free)
• Structs with pointer fields
• Recursion for “friends-of-friends”
• File persistence
• Bidirectional relationships

🗂️ Example Structures #

typedef struct Person {
    char name[30];
    struct Person** friends;
    int num_friends;
} Person;

🧾 Features #

1. Add new people
2. Add friendships (bi-directional links)
3. Print network connections
4. Save / load network from file

💡 Example Run #

Enter name: Alice
Enter name: Bob
Make friends? (Alice, Bob): y
Friendship created!
Alice’s friends: Bob
Bob’s friends: Alice

🏪 Project 7 — Store Receipt Management System #

🎯 Goal #

Create a store checkout and receipt generator that stores items, computes totals, and saves transactions.

🧩 Key Concepts #

• Structs for product, cart item, and receipt
• Enums for product category
• Dynamic arrays for cart items
• File I/O for saving receipts

🗂️ Example Structures #

typedef enum {
    GROCERY,
    ELECTRONICS,
    CLOTHING
} Category;

typedef struct {
    int id;
    char name[50];
    float price;
    Category type;
} Product;

typedef struct {
    Product *product;
    int quantity;
} CartItem;

typedef struct {
    int receipt_id;
    CartItem *items;
    int item_count;
    float total;
} Receipt;

💻 Features #

1. Add products
2. Display catalog
3. Add to cart dynamically
4. Generate and print receipts
5. Save receipts to file

💾 Example Output #

===== STORE MENU =====
1. Add product
2. Purchase
3. Print receipt
4. Exit

Product: Milk
Qty: 2
Total: 91.00
Receipt saved to receipts.txt

🏧 Project 8 — ATM Transaction System #

🎯 Goal #

Simulate an ATM machine where users can create accounts, deposit, withdraw, and view transaction history.

🧩 Key Concepts #

• Structs and enums
• Dynamic transaction list
• File I/O for persistence
• Secure PIN check

🗂️ Example Structures #

typedef enum {
    DEPOSIT,
    WITHDRAWAL,
    BALANCE_CHECK
} TransactionType;

typedef struct {
    TransactionType type;
    float amount;
    char timestamp[30];
} Transaction;

typedef struct {
    int account_number;
    char name[50];
    int pin;
    float balance;
    Transaction* history;
    int transaction_count;
} Account;

💻 Features #

1. Create account
2. Login with PIN
3. Deposit / Withdraw
4. Show balance and transactions
5. Save all data to file

🧾 Example Output #

=== ATM SYSTEM ===
1. Create Account
2. Login
3. Exit

Account created: Alice (Acc #1001)
Deposit 500 → Balance = 500.00
Withdraw 100 → Balance = 400.00

🗂️ Submission & Documentation Checklist #

1. Cover Page #

Include title, student details, course name, instructor name, and date.

2. Project Report (3–5 pages) #

Recommended Sections #

• Introduction
• Design and Approach
• Implementation Details
• Testing and Results
• Conclusion and Future Work

3. Source Code Folder #

• .c files and a Makefile
• Use header files for modularity
• Compile with gcc -Wall -Wextra

4. README File #

• Compilation and execution instructions
• Input/output format description
• Example runs

5. Example Input/Output Files #

Include at least 3 test cases:

• Small, medium, and edge-case dataset.

6. Evaluation Rubric #

💡 Tip: Always run your code through Valgrind to check for memory leaks before submission!