Kotlin Output

Output Functions

println("Hello")
println("World")

print("Hello ")
print("World")

val name = "Alice"
println("Hello, $name!")

val pi = 3.14159
println("Pi: %.2f".format(pi))

🔹 Basic Output Functions

Kotlin provides two main functions for console output:

🔸 println() - Print with New Line

fun main() {
    println("First line")
    println("Second line")
    println("Third line")
    
    // Print empty line
    println()
    println("After empty line")
}

🔸 print() - Print without New Line

fun main() {
    print("Hello ")
    print("beautiful ")
    print("world!")
    println()  // Add new line at the end
    
    print("Numbers: ")
    for (i in 1..5) {
        print("$i ")
    }
}

🔹 Printing Variables

Display different types of data:

fun main() {
    // Different data types
    val name = "Alice"
    val age = 25
    val height = 5.6
    val isStudent = true
    
    // Print variables
    println("Name: $name")
    println("Age: $age")
    println("Height: $height feet")
    println("Is student: $isStudent")
    
    // Print multiple variables
    println("$name is $age years old")
}

🔹 String Templates and Expressions

Use string templates for dynamic output:

fun main() {
    val x = 10
    val y = 20
    
    // Simple variable interpolation
    println("x = $x, y = $y")
    
    // Expression interpolation
    println("Sum: ${x + y}")
    println("Product: ${x * y}")
    println("Average: ${(x + y) / 2.0}")
    
    // Function calls in templates
    val text = "kotlin"
    println("Uppercase: ${text.uppercase()}")
    println("Length: ${text.length}")
    
    // Complex expressions
    val numbers = listOf(1, 2, 3, 4, 5)
    println("Numbers: $numbers")
    println("Max: ${numbers.maxOrNull()}")
    println("Sum: ${numbers.sum()}")
}

🔹 Formatted Output

Control the formatting of your output:

fun main() {
    val pi = 3.14159265
    val price = 29.99
    val count = 42
    
    // Format decimal places
    println("Pi: %.2f".format(pi))
    println("Pi (4 decimals): %.4f".format(pi))
    
    // Format currency
    println("Price: $%.2f".format(price))
    
    // Format integers with padding
    println("Count: %05d".format(count))
    
    // Multiple values
    println("Item: %s, Price: $%.2f, Qty: %d".format("Book", price, count))
    
    // Using string templates (alternative)
    println("Pi rounded: ${"%.3f".format(pi)}")
}

🔹 Multiline Output

Display multiple lines and formatted text:

fun main() {
    val name = "John Doe"
    val course = "Kotlin Programming"
    val grade = 95
    
    // Multiline string
    val report = """
        ================================
        STUDENT REPORT CARD
        ================================
        Name: $name
        Course: $course
        Grade: $grade%
        Status: ${if (grade >= 90) "Excellent" else "Good"}
        ================================
    """.trimIndent()
    
    println(report)
    
    // Table-like output
    println("%-10s %-15s %s".format("ID", "Name", "Score"))
    println("%-10s %-15s %s".format("---", "----", "-----"))
    println("%-10d %-15s %d".format(1, "Alice", 95))
    println("%-10d %-15s %d".format(2, "Bob", 87))
    println("%-10d %-15s %d".format(3, "Charlie", 92))
}