Functions in C++

Introduction

Suppose you want to make juice for yourself. You will follow the following steps:

1. Put fruits and water in a blender.
2. Turn on the juicer.
3. Enjoy the juice after 1 minute.

A function is like a blender that performs a specific action on some ingredients and returns a modified product. We can use the same blender to extract the juice of different fruits. Similarly, functions are reusable, and we can use the same function anytime with different inputs.

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In computer language, a function is a block of code that performs a particular task. It is also given a name.

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Functions in programming are just like mathematical functions. They take something as input, perform some operation on it, and return an output.

Types of functions

In C++, we have two types of functions:

• Library functions
• User-defined functions

Library functions

These functions are also known as built-in functions. They are already defined in the C++ header files such as \<iostream>, \<string>, and \<cmath> etc. We can use these functions by including the relevant header file and then call them later in a program.

User-defined functions

These functions are defined by users according to their needs. We can call them anywhere in the current program.

Why use functions?

We use functions in a program to:

• Make our code reusable
• Divide our code into small modules
• Make the debugging of the program easier
• Make our code neat
• Avoid code repetition

📝 The purpose of a function is to define the code block once and then use it many times.