What is a function in programming?

24 Jun 18:15

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Post cover: What is a function in programming?

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Characteristics of Functions Example of a Function (Method) in Ruby Example of a Function in JavaScript Why Are Functions Needed?

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A function is a fundamental building block of programming that defines a set of instructions or actions that are executed when it is called. Functions allow you to organize code into understandable and reusable blocks. Functions can accept input data (arguments) and return a result.

In different programming languages, functions may have different names, such as "methods" in object-oriented programming. The term method is more commonly heard in discussions about Ruby code, while the term function is used for JS.

Characteristics of Functions

A function has a name by which it can be called.
A function can accept one or more arguments – input data used to perform calculations or actions within the function.
It is a set of instructions that are executed when the function is called.
A function can return a value as a result of its execution.

Conceptually, this is a list of the main characteristics that functions have. Let's look at examples (Ruby and JS)

Example of a Function (Method) in Ruby

def sum_method(a, b)
  # Add two numbers and return the result
  a + b
end

result = sum_method(3, 4)
puts result # Will output 7

Example of a Function in JavaScript

function sumFunction(a, b) {
  // Add two numbers and return the result
  return a + b;
}

let result = sumFunction(3, 4);
console.log(result); // Will output 7

Why Are Functions Needed?

Functions allow you to reuse code and avoid duplication. For example, if you need to perform the same calculations in different places in the program, you can define a function and call it whenever needed. Functions are the foundation ^_^