Examples of Procedural vs Functional and Reactive styles of Programming

functional-reactive-programming.kt

fun procedural() {
    val numbers = (1..10).shuffled().toMutableList()

    // Remove Even Numbers
    var index = 0
    while(index < numbers.count()) {
        if(numbers[index] % 2 == 0) {
            numbers.removeAt(index)
        } else {
            index += 1
        }
    }

    // Double the values
    for(i in numbers.indices) {
        numbers[i] = numbers[i] * 2
    }

    // Sort the Values Smallest to Largest
    for (i in (1 until numbers.count())) {
        val temp = numbers[i]
        var swap = i
        while(swap> 0 && numbers[swap- 1] > temp) {
            numbers[swap] = numbers[swap- 1]
            --swap
        }
        numbers[swap] = temp
    }

    // Print the Results
    for(num in numbers) {
        println(num)
    }
}

fun functional() {
    val numbers = (1..10).shuffled()

    val oddNumbers = numbers.filter { it % 2 != 0 }
    val doubledNumbers = oddNumbers.map { it * 2 }
    val sortedNumbers = doubledNumbers.sorted()

    sortedNumbers.forEach { println(it) }
}

fun reactive() {
    val numbers = (1..10).shuffled().asSequence()

    numbers.filter { it % 2 != 0 }
        .map { it * 2 }
        .sorted()
        .onEach { println(it) }
        .toList()
}