Kotlin If...Else
Making decisions in your Kotlin programs
🤔 What is If...Else?
If...Else statements allow your program to make decisions based on conditions. They execute different code blocks depending on whether a condition is true or false, making your programs smart and interactive.
// Simple if statement
val age = 18
if (age >= 18) {
println("You are an adult!")
}
Types of If Statements
Simple If
Execute code when condition is true
if (score > 90) {
println("Excellent!")
}If...Else
Choose between two options
if (weather == "sunny") {
println("Go outside!")
} else {
println("Stay inside!")
}Else If
Multiple conditions to check
if (grade >= 90) {
println("A")
} else if (grade >= 80) {
println("B")
} else {
println("C")
}If Expression
Return values from if statements
val result = if (x > 0) {
"positive"
} else {
"negative"
}🔹 Basic If Statement
The simplest form checks one condition:
fun main() {
val temperature = 25
if (temperature > 20) {
println("It's warm today!")
}
println("Program continues...")
}Output:
It's warm today!
Program continues...
🔹 If...Else Statement
Choose between two different actions:
fun main() {
val password = "secret123"
if (password == "secret123") {
println("Access granted!")
} else {
println("Access denied!")
}
}Output:
Access granted!
🔹 Multiple Conditions (Else If)
Check several conditions in sequence:
fun main() {
val score = 85
if (score >= 90) {
println("Grade: A - Excellent!")
} else if (score >= 80) {
println("Grade: B - Good job!")
} else if (score >= 70) {
println("Grade: C - Not bad!")
} else {
println("Grade: F - Study harder!")
}
}Output:
Grade: B - Good job!
🔹 If as Expression
In Kotlin, if can return a value:
fun main() {
val age = 16
val status = if (age >= 18) {
"Adult"
} else {
"Minor"
}
println("Status: $status")
// Short form
val message = if (age >= 18) "Can vote" else "Cannot vote"
println(message)
}Output:
Status: Minor
Cannot vote
🔹 Logical Operators
Combine multiple conditions:
fun main() {
val age = 25
val hasLicense = true
// AND operator (&&)
if (age >= 18 && hasLicense) {
println("Can drive!")
}
// OR operator (||)
val day = "Saturday"
if (day == "Saturday" || day == "Sunday") {
println("It's weekend!")
}
// NOT operator (!)
val isRaining = false
if (!isRaining) {
println("Good weather for a walk!")
}
}Output:
Can drive!
It's weekend!
Good weather for a walk!