📘 1. Function Structure in C++


returnType functionName(parameters) {
    // body
    return value; // optional
}

🛠️ 2. Types of Functions (User-defined)

Type Description
No return, No parameter Fixed message or task
Return + No parameter Output return hota hai
No return + With parameter Kaam karta hai, kuch return nahi
Return + With parameter ✅ Most useful — input bhi le, output bhi de

🔹 Example 1: No return, no parameters


void greet() {
    cout << "Hello!" << endl;
}

🧠 Use: greet();

🔹 Example 2: Return + no parameter


int giveFive() {
    return 5;
}

🧠 Use: int x = giveFive();

🔹 Example 3: No return, with parameters


void printSum(int a, int b) {
    cout << "Sum: " << (a + b) << endl;
}

🧠 Use: printSum(3, 4);

🔹 Example 4: Return + parameters ✅


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