Careeroza

Real World Example

Cinema Seat Booking

A movie ticket app like BookMyShow keeps the seat map of a screen as a grid: rows and columns with a fixed size. A 2D array fits naturally. Fitness apps similarly keep 7 days of step counts in an IntArray.

Example

Booking seats on a small screen and printing the map:

fun main() {
    val rows = 4
    val cols = 6
    val booked = Array(rows) { BooleanArray(cols) }

    fun book(seat: String): Boolean {
        val r = seat[0] - 'A'
        val c = seat.substring(1).toInt() - 1
        if (r !in 0 until rows || c !in 0 until cols) return false
        if (booked[r][c]) return false
        booked[r][c] = true
        return true
    }

    println("Book B3: ${book("B3")}")
    println("Book B4: ${book("B4")}")
    println("Book B3 again: ${book("B3")}")
    println("Book Z9: ${book("Z9")}")

    println("   SCREEN THIS WAY")
    for (r in 0 until rows) {
        val line = booked[r].joinToString(" ") { if (it) "X" else "_" }
        println("${'A' + r}  $line")
    }
    val free = booked.sumOf { row -> row.count { !it } }
    println("Seats available: $free")
}

Output

Book B3: true
Book B4: true
Book B3 again: false
Book Z9: false
   SCREEN THIS WAY
A  _ _ _ _ _ _
B  _ _ X X _ _
C  _ _ _ _ _ _
D  _ _ _ _ _ _
Seats available: 22

Practice

Exercise: Create an IntArray of 7 daily step counts: 5000, 7200, 10400, 3000, 12000, 8000, 9500. Print the total, the average as a whole number, and on which day number (1-based) the maximum steps were walked.

Show answer
fun main() {
    val steps = intArrayOf(5000, 7200, 10400, 3000, 12000, 8000, 9500)
    println("Total: ${steps.sum()}")                       // 55100
    println("Average: ${steps.average().toInt()}")         // 7871
    println("Best day: ${steps.indexOf(steps.max()) + 1}") // 5
}