What is a function? - Programming
Tags: webdev, programming, beginners, codenewbie
Published: 2022-12-09 16:04:13


Programming is a set of instructions that you give to a computer to perform a specific task.

With functions, you could simplify the instructions you give computers.

Functions make programming more fun because of the benefits they provide.

In this article, you will learn what a function is, the types of functions, and the importance of functions.


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## What is a function?
A function is a block of code you can use as much as you want.

If you’re writing a program that sends out “Good morning” messages to over 1000 users. You will need a function for that.

Functions are available in different programming languages, but they may have different names. Names like subroutines, methods, and procedures.

For example, in Visual Basic (VB) or VB.NET, a function that does not return a value is called a subroutine. In C#, functions and subroutines are known as “methods.” In Python, there is no difference between functions and subroutines.

Functions have different semantics in different programming languages. Even in OOP (object-oriented programming), a function may be used as a method.

## Types of functions in programming
In programming, there are two types of functions which are;

1. Built-in functions

2. User-defined functions


**Built-in functions**

These are functions that are pre-built into the memory of the programming language. With these kinds of functions, you do not have to worry about bug fixes or their implementation. They are there to simplify the coding experience for you.

In Python, there are built-in functions like `print()`, `type()`, and `input()`.

In C, there are built-in functions like `printf()`, `scanf()`, and `gets()`.

In Java and JavaScript, there are built-in functions like `toLowerCase()`, `charAt()`, `concat()`, and so on.

Built-in functions vary between different programming languages as they have different semantics.

**User-defined functions**

These are functions you can write on your own. As the name implies, it is the user who gets to define the functions.

These functions make up the core coding experience in programming. You do not need to learn how to write built-in functions, but you do need to learn how to write your own function. Check out this tutorial to learn [how to write functions in Python](https://dev.to/ezinne_anne/what-are-functions-in-python--2nho
)

## Importance of functions in programming

**Functions are reusable**

This is most applicable to built-in functions. When you do not have to worry about the implementation, you just have to use it. For instance, programming would be much more complicated if you had to write a print function every time you wanted to run your code.

**Functions hide the complexity of code**

This is most applicable in built-in functions. When you do not have to worry about the implementation, you just have to use it. For instance, programming would be much more complicated if you had to write a print function every time you wanted to run your code.

**Reduce bugs**

Functions reduce bugs, and they make it easier to run tests in your code. When running tests, you run into errors in your function. You could change the function you want without affecting the rest of your code.

**Simpler code**

When writing functions, you can split your code into different functions. Place them in different modules. In your main module, you can import those functions and apply them. This makes your code simpler to read, understand, and debug.

## Conclusion
Functions are one of the core concepts in programming. They hide complexity and give you the power to build great applications. Because of the differences in programming languages. They are generally referred to as “callable units.”

Python is one of the most popular programming languages. If you want to learn [how to create functions in Python, check out this tutorial I made about it](https://dev.to/ezinne_anne/what-are-functions-in-python--2nho).