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Logical NOT Operator

Part of the Fundamentals section of Coddy's GO journey — lesson 26 of 109.

The logical NOT operator (!) reverses a boolean value. It turns true into false and false into true.

Create a program that uses the NOT operator to check if a number is not even:

num := 7
isEven := num%2 == 0
isOdd := !isEven
fmt.Println("Is", num, "odd?", isOdd)

This outputs:

Is 7 odd? true

The NOT operator inverted isEven (which was false for 7) to true, correctly identifying that 7 is odd.

Challenge

Beginner

In this challenge, you'll practice using the logical NOT operator (!) in Go.

The logical NOT operator inverts a boolean value: true becomes false and false becomes true.

We've provided a boolean variable isRaining. Your task is to use the NOT operator to invert its value and store the result in the result variable.

Cheat sheet

The logical NOT operator (!) reverses a boolean value. It turns true into false and false into true.

num := 7
isEven := num%2 == 0
isOdd := !isEven
fmt.Println("Is", num, "odd?", isOdd)

This outputs:

Is 7 odd? true

The NOT operator inverted isEven (which was false for 7) to true, correctly identifying that 7 is odd.

Try it yourself

package main

import "fmt"

func main() {
	// Boolean variable
	isRaining := true
	
	// TODO: Use the NOT operator (!) to invert the value of isRaining
	// and store the result in the variable below
	result := isRaining
	
	// Print the original value and the inverted value
	fmt.Println("Original value:", isRaining)
	fmt.Println("After using NOT operator:", result)
}

Test yourself

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

All lessons in Fundamentals

1Introduction to Go

What is Go?Hello World Println Go Comments

4Comparison & Logical Operators

Comparison Operators - Part 1 Comparison Operators - Part 2 Logical AND Operator Logical OR OperatorLogical NOT OperatorOperator Precedence Basics Recap - Making Comparisons

7Control Flow: Loops

What The `for` Loop Explained For Loop - Basic For Loop - Condition Only The `break` Keyword The `continue` Keyword Nested Loops Recap - Repeating Actions

10Composite Types: Arrays

Introduction to Arrays Declaring Arrays Initializing Arrays Accessing Array Elements Array Length with `len`Iterating Over Arrays Multi-dimensional Arrays

13Composite Types: Structs

Defining Custom Types Creating Struct Instances Accessing Struct Fields Pointers to Structs Initializing Structs Embedded Structs Anonymous Structs Recap - Custom Data Structures

2Variables and Basic Data Types

What is a variable Type Inference with `:=`Integers (int)Floating-Point Numbers Booleans Strings Zero Values Constants Naming Conventions Recap - Variables and Types

5Basic Input/Output

Formatted Output Format Verbs Printing Types Getting Basic User Input Recap - Input and Output

8Functions

Understanding Functions Declaring a Function Calling Functions Function Parameters Returning a Single Value Returning Multiple Values Named Return Values Function Scope Basics Recap - Creating Reusable Code

11Composite Types: Slices

Introduction to Slices Declaring Slice Literals Creating Slices with `make`Slice Length vs Capacity Accessing Slice Elements Appending Elements Slicing Existing Slices/Arrays Iterating Over Slices Copying Slices Recap - Dynamic Lists

14Basic Error Handling

The Concept of Errors The `error` Interface Functions Returning Errors Checking for Errors Creating Simple Errors Creating Formatted Errors Basic Error Handling Recap - Handling Problems