Part 1 — Definition

A Function is a block of code that performs a specific task. It runs only when it is called. Functions help in Code Reusability (write once, use many times) and make the program more modular and easier to debug.

Part 2 — Syntax

// 1. Prototype
void greet();

int main() {
    // 2. Call
    greet();
    return 0;
}

// 3. Definition
void greet() {
    cout << "Hello!";
}

Part 3 — Example

Problem: Create a function that calculates the sum of two numbers.

int add(int a, int b) {
    return a + b;
}

int main() {
    int res = add(10, 20);
    cout << "Sum: " << res;
    return 0;
}

Output: Sum: 30

Part 4 — Video

Video: Coming Soon

Part 1 — Definition

Recursion is the process in which a function calls itself directly or indirectly. It is used to solve problems that can be broken down into smaller, similar sub-problems (like Factorials or Fibonacci sequences). Every recursive function must have a Base Case to stop the recursion.

Part 2 — Syntax

void recurse() {
    if (base_condition) return;
    recurse(); // Self call
}

Part 3 — Example

Problem: Calculate the Factorial of a number using recursion.

int fact(int n) {
    if (n <= 1) return 1; // Base case
    return n * fact(n - 1); // Recursive call
}

Observation: If you forget the base case, the program will crash with a "Stack Overflow" error.

Part 4 — Video

Video: Coming Soon