Declare a Function

Part of the Fundamentals section of Coddy's JavaScript journey — lesson 45 of 77.

A function is a sequence of code that has a name. The purpose of a function is to reuse a piece of code multiple times.

For example, take a look at this code:

console.log("Welcome to Coddy");
console.log("New session...");
console.log("Welcome to Coddy");
console.log("Another session...");
console.log("Welcome to Coddy");

We use the same code console.log("Welcome to Coddy") over and over again. Another issue with this code is that if we wanted to change the message: Welcome to Coddy to something different, like "Welcome aboard" it would have to change 3 different lines of code. To solve this issue, we will use functions.

To declare a function, we use the following syntax:

function functionName() {
    code;
}

For our example, we will create a function named greet and it will look like this:

function greet() {
    console.log("Welcome to Coddy");
}

To use/call/execute the function, we write greet():

greet();
console.log("New session...");
greet();
console.log("Another session...");
greet();

This will result in the same output as above.

Note: It is best practice to write the function code before calling it, so your code is easier to read and understand.

Challenge

Easy

Write a program that gets one input, a number (given). The input number indicates how many times to execute the below function.

Create a function that calculates the sum of all of the numbers between 1 and 10000 (including) and prints it, name the function however you like.

Note! In your code, write the function before it's call/execution statements.

Cheat sheet

A function is a sequence of code that has a name, used to reuse code multiple times.

To declare a function:

function functionName() {
    code;
}

To call/execute a function:

functionName();

Example:

function greet() {
    console.log("Welcome to Coddy");
}

greet(); // calls the function

Best practice: It is best practice to write functions before calling them.

Try it yourself

// Write the function below


let n = parseInt(inp); // Don't change this line

// Execute your function n times with a loop

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Fundamentals

1Introduction

The Language Hello World!Comments Code Structure

4Operators Part 2

Logical Operators Part 1 Logical Operators Part 2 Recap - Simple Logic Logical Operators Part 3 Type Coercion

7Bill Split Calculator

Welcome Message Calculating The Tip And Total

Splitting The Bill

Formatted Output

10FizzBuzz with a Twist

Game Overview The FizzBuzz Function

Looping The Numbers

Adding The Twist

13Grocery List Tracker

Project Overview Add Item

Remove Item

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