Logical Operators Part 1

Part of the Fundamentals section of Coddy's C journey — lesson 21 of 63.

Logical operators are used to check combinations of comparisons that return 1 (true) or 0 (false).

For example, the following statement contains two comparisons:

Is 5 greater than 3 and less than 6?

Operator	Meaning	Example
`&&`	And - `1` if all operands are `1`	`a && b`
`\|\|`	Or - `1` if any operand is `1`	`a \|\| b`
`!`	Not - `1` if the operand is `0`	`!a`

Let's see some examples:

5 is greater than 3 and 1 equals 1:

int b1 = (5 > 3) && (1 == 1); // holds 1 (true)

Explanation: All of the operands are 1, so b1 will hold 1 (and operation is 1 if both operands are 1) .

5 is not equal to 4 or 5 equals 2:

int b2 = !(5 == 4) || (5 == 2); // holds 1 (true)

Explanation: The first operand (5 != 4) is 1 so b2 is also 1 (or operation is 1 if either one of the operands is 1)

Challenge

Easy

You are given code. Replace the question marks of the variables int b1 and int b2 so that int b3 holds 1 (true).

Take a moment to analyze the condition and think about what values would make it true.

There are many right solutions!

Cheat sheet

Logical operators are used to check combinations of comparisons that return 1 (true) or 0 (false).

Operator	Meaning	Example
`&&`	And - `1` if all operands are `1`	`a && b`
`\|\|`	Or - `1` if any operand is `1`	`a \|\| b`
`!`	Not - `1` if the operand is `0`	`!a`

Examples:

int b1 = (5 > 3) && (1 == 1); // holds 1 (true)

int b2 = !(5 == 4) || (5 == 2); // holds 1 (true)

Try it yourself

#include <stdio.h>

int main() {
    // Type your code below
    int b1 = ?;
    int b2 = ?;
    int b3 = b1 || b2;
    
    // Don't change the line below
    printf("b3 = %d", b3);
    return 0;
}

Test yourself

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

All lessons in Fundamentals

1Introduction

C Language Hello World!Comments Basic Program Structure

4Control Flow

If Statement If - Else Else-If Switch Case Ternary Conditional Operator Recap Challenge Nested If - Else

7Functions

Declare a Function Return Types Parameters Recap Challenge #1 Recursion Basics Function Prototypes Recap Challenge #2

3Operators

Arithmetic Operators Modulo Operator Increment/Decrement Assignment Operators Relational OperatorsLogical Operators Part 1Logical Operators Part 2 Logical Operators Part 3 Recap Challenge

6Loops

For Loop While Loop Do While Loop Break Continue Recap Challenge #1 Nested Loops Infinite Loops Recap Challenge #2

9Final Challenges

Grades Peaks TV