Modulo Operator

The modulo operator % returns the remainder after division. While regular division tells you how many times one number fits into another, modulo tells you what's left over.

fun main() {
    println(10 % 3)  // Prints: 1 (10 = 3*3 + 1)
    println(15 % 5)  // Prints: 0 (15 = 5*3 + 0)
    println(7 % 4)   // Prints: 3 (7 = 4*1 + 3)
}

One of the most common uses of modulo is checking if a number is even or odd. If a number divided by 2 has no remainder, it's even:

fun main() {
    val number = 8
    println(number % 2)  // Prints: 0 (even)
    
    val another = 7
    println(another % 2) // Prints: 1 (odd)
}

Modulo is incredibly useful in programming, from determining if a year is a leap year, to cycling through a list of items, to formatting output in rows. You'll encounter it frequently as you continue learning.