Swift Boolean

Booleans are one of the most fundamental data types in Swift. They represent logical values: true or false. Boolean values are essential for controlling program flow through conditional statements and loops.

In this tutorial, you will learn about boolean data type in Swift, how to use them in conditional statements and loops, with examples.

---

Boolean Data Type

In Swift, the Boolean type is Bool. It can hold one of two values:

• true: Represents a logically true condition.
• false: Represents a logically false condition.

Here’s an example of declaring Boolean variables:

File: main.swift

let isSwiftFun: Bool = true
let isProgrammingHard: Bool = false

print("Is Swift fun? \(isSwiftFun)")
print("Is programming hard? \(isProgrammingHard)")

Output:

---

Using Booleans in Conditional Statements

Boolean values are commonly used in conditional statements to determine the flow of execution:

File: main.swift

let hasCompletedTask = true

if hasCompletedTask {
    print("Great job! You've completed the task.")
} else {
    print("Keep going! You're almost there.")
}

Explanation:

• The if statement checks the value of hasCompletedTask.
• If the value is true, the first block of code is executed; otherwise, the else block is executed.

Output:

---

Combining Booleans with Logical Operators

Swift provides logical operators to combine or negate Boolean values:

• &&: Logical AND
• ||: Logical OR
• !: Logical NOT

File: main.swift

let isRaining = false
let hasUmbrella = true

if !isRaining || hasUmbrella {
    print("You can go outside.")
} else {
    print("Stay indoors to avoid getting wet.")
}

Explanation:

• The !isRaining negates the value of isRaining, making it true.
• The || operator checks if at least one of the conditions (!isRaining or hasUmbrella) is true.
• If either condition is true, the program executes the first block of code.

Output:

---

Booleans in Loops

Booleans are also used in loops to control repetition:

File: main.swift

var isRunning = true
var counter = 0

while isRunning {
    print("Counter: \(counter)")
    counter += 1

    if counter == 5 {
        isRunning = false
    }
}

Explanation:

• The while loop continues as long as isRunning is true.
• Inside the loop, counter is incremented, and the loop terminates when counter reaches 5.

Output:

---

Conclusion

The Boolean type is an essential part of Swift programming, enabling logic and control flow in your applications.