Functions are an essential part of any programming language, and C++ is no exception. In C++, functions are used to group a set of statements together, making the code more modular and easier to understand. C++ offers different types of functions, each serving a specific purpose. In this article, we will explore the various function types in C++ and provide examples to illustrate their usage.

### Void Functions:

A void function, as the name suggests, does not return any value. It is primarily used to perform a task without producing a result. Here’s an example:

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#include <iostream> void greet() { std::cout << "Hello! Welcome to the world of C++!" << std::endl; } int main() { greet(); // Calling the greet function return 0; } |

In the above example, the greet() function is defined as a void function, which simply prints a welcome message to the console. The function is called from the main() function, and it does its job without returning any value.

### Functions with Parameters:

Functions in C++ can also take parameters, which are values passed to the function for its operations. Here’s an example of a function that calculates the sum of two numbers:

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#include <iostream> int sum(int a, int b) { return a + b; } int main() { int num1 = 5; int num2 = 10; int result = sum(num1, num2); // Calling the sum function with arguments std::cout << "The sum is: " << result << std::endl; return 0; } |

In the above example, the sum() function takes two parameters a and b of type int. It calculates their sum using the + operator and returns the result. The main() function calls sum() with num1 and num2 as arguments, and the returned value is stored in the result variable.

### Functions with Return Types:

C++ functions can have return types other than void. These functions return a value of the specified type. Here’s an example of a function that calculates the factorial of a number:

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#include <iostream> int factorial(int n) { int result = 1; for (int i = 1; i <= n; ++i) { result *= i; } return result; } int main() { int number = 5; int fact = factorial(number); // Calling the factorial function std::cout << "The factorial of " << number << " is: " << fact << std::endl; return 0; } |

In the above example, the factorial() function takes an integer n as a parameter and calculates its factorial using a loop. The result is returned to the main() function, where it is displayed on the console.

### Recursive Functions:

C++ allows functions to call themselves, which is known as recursion. Recursive functions are useful when a problem can be broken down into smaller sub-problems of the same type. Here’s an example of a recursive function to calculate the nth Fibonacci number:

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#include <iostream> int fibonacci(int n) { if (n <= 1) { return n; } return fibonacci(n - 1) + fibonacci(n - 2); } int main() { int n = 7; int fib = fibonacci(n); // Calling the fibonacci function std::cout << "The " << n << "th Fibonacci number is: " << fib << std::endl; return 0; } |

In the above example, the fibonacci() function calls itself recursively to calculate the nth Fibonacci number. The base case checks if n is less than or equal to 1 and returns n. Otherwise, it calls itself with n-1 and n-2 as arguments and returns the sum of the two previous Fibonacci numbers.

These are just a few examples of the different function types in C++. By understanding and utilizing these function types, you can write more organized and efficient code in C++.