Kotlin If…Else

Welcome to The Coding College! In this tutorial, we will dive into the if…else statement in Kotlin, which is essential for decision-making in programming. Learning how to use conditional statements effectively will help you write dynamic and responsive code.

What is If…Else in Kotlin?

The if…else statement in Kotlin is used to execute a block of code based on a condition. It evaluates a Boolean expression and runs the appropriate code block depending on whether the condition is true or false.

Basic Syntax:

if (condition) {
    // code block to execute if condition is true
} else {
    // code block to execute if condition is false
}

Example of If…Else

Let’s look at a simple example:

fun main() {
    val score = 85
    if (score >= 50) {
        println("You passed the test!")
    } else {
        println("You failed the test.")
    }
}

Output:

You passed the test!

Kotlin If Statement

The if statement can be used independently to execute code when a condition is true.

Example:

fun main() {
    val isRaining = true
    if (isRaining) {
        println("Take an umbrella!")
    }
}

Kotlin If…Else Statement

The if…else statement provides an alternative block of code to execute when the condition is false.

Example:

fun main() {
    val age = 16
    if (age >= 18) {
        println("You are eligible to vote.")
    } else {
        println("You are not eligible to vote.")
    }
}

Kotlin If…Else If…Else

For multiple conditions, you can use the if…else if…else construct.

Example:

fun main() {
    val score = 75
    if (score >= 90) {
        println("Excellent!")
    } else if (score >= 75) {
        println("Good job!")
    } else if (score >= 50) {
        println("You passed!")
    } else {
        println("Better luck next time.")
    }
}

Output:

Good job!

Kotlin If Expression

In Kotlin, the if statement is an expression, meaning it can return a value. This allows you to assign the result of an if condition directly to a variable.

Example:

fun main() {
    val age = 20
    val status = if (age >= 18) "Adult" else "Minor"
    println("You are an $status.")
}

Output:

You are an Adult.

Nested If…Else

You can nest if...else statements to handle complex conditions.

Example:

fun main() {
    val num = 0
    if (num >= 0) {
        if (num == 0) {
            println("The number is zero.")
        } else {
            println("The number is positive.")
        }
    } else {
        println("The number is negative.")
    }
}

Output:

The number is zero.

Practical Example: Grade Calculator

Here’s a practical example using if…else to calculate grades based on marks:

fun main() {
    val marks = 82
    val grade = if (marks >= 90) {
        "A+"
    } else if (marks >= 80) {
        "A"
    } else if (marks >= 70) {
        "B"
    } else if (marks >= 60) {
        "C"
    } else {
        "F"
    }
    println("Your grade is: $grade")
}

Output:

Your grade is: A

Best Practices for If…Else

  1. Simplify Conditions: Avoid overly complex conditions for readability.
  2. Use When for Multiple Conditions: If there are many else if blocks, consider using a when statement for better clarity.
  3. Avoid Redundancy: Simplify nested conditions whenever possible.

Learn More on The Coding College

Mastering if…else in Kotlin is a fundamental step in programming. Visit The Coding College for more Kotlin tutorials, coding guides, and programming tips to enhance your skills.

Conclusion

The if…else statement is a powerful tool for decision-making in Kotlin. By mastering its syntax and use cases, you can write more dynamic and efficient code.

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