Logical Operators Part 1

Part of the Fundamentals section of Coddy's C# journey — lesson 21 of 69.

Logical operators are used to combine or modify boolean expressions. They are essential for creating complex conditions in your code.

For example, the following statement contains two comparisons:

Is 5 greater than 3 and less than 6?

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

Let's see some examples:

5 is bigger than 3 and 1 equals 1:

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

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

5 does not equal 4 or 5 equals 2:

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

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

1 does not equal 1 or false:

bool b3 = !(1 == 1) || false; // holds false

Explanation: All of the operands are false, so b3 will hold false (or operation).

not (3 is bigger than 4):

bool b4 = !(3 > 4); // holds true

Explanation: The operand is false, so b4 will hold true (not operation).

not (5 bigger than 10 or 5 bigger than 1):

bool b5 = !(5 > 10 || 5 > 1); // holds false

Explanation: 5 > 10 || 5 > 1 is true (one of the operands is true), so in total b5 is false (not operation).

Challenge

Beginner

You are given a code. Replace the question marks of the variables b1 and b2 so that b3 holds true.

There are many right solutions!

Cheat sheet

Logical operators are used to combine or modify boolean expressions:

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

Examples:

bool b1 = (5 > 3) && (1 == 1); // true - both operands are true
bool b2 = !(5 == 4) || (5 == 2); // true - first operand is true
bool b3 = !(1 == 1) || false; // false - both operands are false
bool b4 = !(3 > 4); // true - negates false to true
bool b5 = !(5 > 10 || 5 > 1); // false - negates true to false

Try it yourself

using System;

public class Program {
    public static void Main(string[] args) {
        // Type your code below
        bool b1 = ?;
        bool b2 = ?;
        bool b3 = b1 || b2;
        
        // Don't change the line below
        Console.WriteLine("b3 = " + b3);
    }
}