Kotlin Basics Made Easy

This document provides a list of basic Kotlin programming commands and concepts to help you get started with writing and executing Kotlin code.

Program Structure

• fun main() { ... }: Main function where the program starts execution.
• //: Comment line.

Variables

• val variableName = value: Define a read-only variable.
• var variableName = value: Define a mutable variable.
• variableName: Access the value of a variable.

Data Types

• Int: Integer type.
• Double: Floating-point type.
• String: String type.
• Boolean: Boolean type.

Input and Output

• println(text): Print text to the console.
• readLine(): Read input from the user.

Conditional Statements

• if (condition) { ... }: Basic if statement.
• if (condition) { ... } else { ... }: If-else statement.
• when (variable) { ... }: Switch statement equivalent.

Loops

• for (item in collection) { ... }: For loop.
• while (condition) { ... }: While loop.
• do { ... } while (condition): Do-while loop.

Functions

• fun functionName(parameters): ReturnType { ... }: Define a function.
• functionName(arguments): Call a function.

Collections

• val listName = listOf(value1, value2, value3): Define a read-only list.
• val mutableListName = mutableListOf(value1, value2, value3): Define a mutable list.
• val mapName = mapOf(key1 to value1, key2 to value2): Define a read-only map.

String Operations

• string.length: Get the length of a string.
• string.substring(startIndex, endIndex): Extract a substring.

Null Safety

• var nullableVar: String? = null: Declare a nullable variable.
• nullableVar?.length: Safe call operator to avoid NullPointerException.

Exception Handling

• try { ... } catch (e: Exception) { ... }: Handle exceptions.

Lambda Functions

• val lambdaName: (Type) -> ReturnType = { parameters -> body }: Define a lambda function.
• lambdaName(arguments): Call a lambda function.

These commands and concepts should help you get started with basic Kotlin programming.

Let me know if you need any further adjustments!