C# Booleans

C# Booleans

In programming, you often need a data type that can only hold one of two possible values, such as YES/NO, ON/OFF, or TRUE/FALSE. For this, C# has a bool data type.

A boolean variable can only take the values true or false.

Declaring Booleans

You define a boolean variable using the bool keyword.

bool isCSharpFun = true;
bool isFishTasty = false;

Console.WriteLine(isCSharpFun);   // Outputs True
Console.WriteLine(isFishTasty);   // Outputs False

Boolean Expressions

A boolean expression is a C# statement that evaluates to true or false. You use comparison operators (like >, <, ==) to build these expressions.

This is highly useful for building logic and finding answers.

using System;

class Program {
  static void Main() {
    int x = 10;
    int y = 9;
    // Is x greater than y?
    Console.WriteLine(x > y); // Returns True, because 10 is greater than 9
    // Is x equal to 10?
    Console.WriteLine(x == 10); // Returns True
    // Is 10 equal to 15?
    Console.WriteLine(10 == 15); // Returns False
  }
}

Booleans are the foundation for all decision-making in programming. We will use them heavily in the next chapter when we discuss If...Else statements!

Real-World Example

Let's think of a real-life situation where we can apply a boolean logic. Imagine a system that checks if a user is old enough to vote.

using System;

class Program {
  static void Main() {
    int myAge = 25;
    int votingAge = 18;
    // Output true if myAge is greater than or equal to votingAge
    Console.WriteLine(myAge >= votingAge); // Returns True
  }
}