Menu

Tech

English

Comments

Part of the Fundamentals section of Coddy's Swift journey — lesson 3 of 86.

Comments are notes you write inside your code. The compiler completely ignores them - they exist only to help humans understand the code.

To write a single-line comment, use //. Everything after // until the end of the line is ignored:

// This is a comment
print("Hello!")

A comment can also be written at the end of a line, after the code:

print("Hello!") // This prints Hello!

For comments that span several lines, use /* to start and */ to end:

/* This is a multi-line comment.
   The compiler ignores all of it. */
print("Welcome!")

Comments can also temporarily disable a line of code without deleting it:

// print("This line will NOT run")
print("This line will run")

Challenge

Beginner

Fix the code so that only Hello, Swift! is printed.

Replace the ? with the symbols that turn a line into a comment
The line printing Goodbye! should become a comment so it does NOT run
Only change the line that starts with ?

Cheat sheet

Comments in Swift:

Notes for humans - the compiler ignores them
Can disable code temporarily without deleting it

Single-line comment:

// This is a comment
print("Hello!") // Comment after code

Multi-line comment:

/* This is a
   multi-line comment */

Disabling code:

// print("This will NOT run")
print("This will run")

Try it yourself

// Type your code below
? print("Goodbye!")
print("Hello, Swift!")

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

4Operators Part 1

Arithmetic Operators Modulo Operator Compound Assignment Recap - Simple Math Comparison Operators

7Basic IO

Print Function String Interpolation ReadLine Input Type Conversion Recap - Till 120 Recap - True or False

10Functions

Declare A Function Parameters And Arguments Return Values Argument Labels Recap - Sigma Function Recap - Validation Function Default Values

13Iterating Over Sequences

Iterating Over Elements The Enumerated Method Iterating Over Strings P1 Iterating Over Strings P2

16Final Challenges

Flat Asterisk Pyramid Pattern Finder What To Buy

2Variables

Let vs Var Type Annotations Numbers String Boolean Naming Conventions Recap - Initialize Variables

5Operators Part 2

Logical Operators Part 1 Logical Operators Part 2 Recap - Simple Logic Logical Operators Part 3 Ternary Operator

8Bill Split Calculator

Welcome Message Getting Input

Project lesson

Calculating Tip And Total

Project lesson

Splitting The Bill

Project lesson

Formatted Output

Project lesson

11FizzBuzz with a Twist

Game Overview The FizzBuzz Function

Project lesson

Looping The Numbers

Project lesson

Adding The Twist

Project lesson

14Arrays Advanced

Array Slicing Part 1 Array Slicing Part 2 Sequence Operators The Contains Method