Kotlin - 3 - Kotlin Syntax Basics

Kotlin is known for its concise and expressive syntax, which simplifies many common programming tasks. Whether you’re new to Kotlin or transitioning from another programming language, understanding the basics of Kotlin’s syntax is crucial. In this guide, we’ll explore the fundamental syntax elements of Kotlin, including variables, data types, and control flow.

Variables and Data Types

Declaring Variables

In Kotlin, you declare variables using the val (immutable) or var (mutable) keyword, followed by the variable name and type. Here’s an example:

val name: String = "Hello" // Immutable variable
var age: Int = 30 // Mutable variable

val creates an immutable (read-only) variable.
var creates a mutable (modifiable) variable.

Type Inference

Kotlin has excellent type inference, which means you can often omit the type declaration when the type can be inferred from the assigned value:

val greeting = "Hi, Kotlin!" // Type inferred as String
var count = 44 // Type inferred as Int

Kotlin Basic Data Types

Kotlin provides a range of built-in data types:

Int: Represents 32-bit signed integers.
Long: Represents 64-bit signed integers.
Short: Represents 16-bit signed integers.
Byte: Represents 8-bit signed integers.
Double: Represents double-precision 64-bit floating-point numbers.
Float: Represents single-precision 32-bit floating-point numbers.
Char: Represents a single character.
Boolean: Represents true or false values.

Operators in Kotlin

Kotlin supports a wide range of operators for performing operations on variables and values. Here are some common operators:

Arithmetic Operators

val a = 10
val b = 5

val sum = a + b // Addition
val difference = a - b // Subtraction
val product = a * b // Multiplication
val quotient = a / b // Division
val remainder = a % b // Remainder

Comparison Operators

val x = 20
val y = 30

val isEqual = x == y // Equal to
val isNotEqual = x != y // Not equal to
val isGreaterThan = x > y // Greater than
val isLessThan = x < y // Less than
val isGreaterOrEqual = x >= y // Greater than or equal to
val isLessOrEqual = x <= y // Less than or equal to

Logical Operators

val isTrue = true
val isFalse = false

val andResult = isTrue && isFalse // Logical AND
val orResult = isTrue || isFalse // Logical OR
val notResult = !isTrue // Logical NOT

Increment and Decrement Operators

var counter = 5

counter++ // Increment by 1 (counter is now 6)
counter-- // Decrement by 1 (counter is now 5)

Kotlin Control Flow

Kotlin offers various control flow constructs for making decisions and repeating actions.

If-Else Expression

val age = 18

val result = if (age >= 18) {
    "You can vote."
} else {
    "You cannot vote."
}

When Expression (Replacement for Switch)

val day = 2
val dayOfWeek = when (day) {
    1 -> "Monday"
    2 -> "Tuesday"
    3 -> "Wednesday"
    4 -> "Thursday"
    5 -> "Friday"
    else -> "Weekend"
}

While Loop

var i = 0
while (i < 5) {
    println(i)
    i++
}

For Loop (Ranges)

for (i in 1..5) {
    println(i)
}

For Loop (Collections)

val fruits = listOf("Apple", "Banana", "Cherry")
for (fruit in fruits) {
    println(fruit)
}

Conclusion

Kotlin’s syntax combines simplicity and expressiveness, making it a powerful language for various software development tasks. Whether you’re working on Android app development, web development, or backend services, understanding these Kotlin syntax basics is essential. By mastering these foundational concepts, you’ll be well on your way to becoming proficient in Kotlin programming.

Kotlin – 3 – Kotlin Syntax Basics