Functions in C++: Declaration, Definition, and Examples

Functions in C++
Functions in C++ are reusable blocks of code designed to perform specific tasks.
They help in breaking a program into smaller, manageable, and reusable
components, improving modularity and code readability.

1. Syntax of a Function
General Syntax:

return_type function_name(parameter_list) {
// Function body
return value; // Optional for void functions
}

Example:

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


2. Types of Functions in C++
2.1 Built-in Functions
Functions provided by C++ standard libraries (e.g., sqrt(), pow()).

Example:

#include <cmath>
cout << sqrt(16); // Output: 4

2.2 User-Defined Functions
Functions created by the programmer to perform specific tasks.

, Example:

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


3. Function Components
3.1 Return Type
Specifies the type of value the function returns. Use void if the function does not
return any value.

Example:

int square(int x) {
return x * x;
}

3.2 Function Name
The name used to call the function.

Example:

int calculate() {
return 42;
}

3.3 Parameters
Variables passed to a function to provide input.

Example:

void display(int age) {
cout << "Age: " << age;
}