如何使用 Kotlin lambda 表达式求奇数和偶数的乘积

Question

如何完成给定的程序代码，以便程序要求用户输入五个整数，输入的数字中只会保留正数，用于显示奇数和偶数的乘积数字？在 lambda 上下文中，我需要使用 forEach 方法。

fun main() {
    var nums = IntArray(5)
    var index = 0

    nums.forEach {
    // code to get input from the user
    }

    var prodOdd = 1
    var prodEven = 1

    nums.forEach {
    // code to accumulate the products of odd and even
    }

    println("The product of ${nums.filter { //some code } } is $prodEven")
    println("The product of ${nums.filter { //some code } } is $prodOdd")
}


GOAL / TEST CASES

Example Output 1
Enter number 1: 1
Enter number 2: 2
Enter number 3: 3
Enter number 4: 4
Enter number 5: 5
The product of [2, 4] is 8
The product of [1, 3, 5] is 15

Example Output 2
Enter number 1: 8
Enter number 2: 3
Enter number 3: 7
Enter number 4: 2
Enter number 5: 4
The product of [8, 2, 4] is 64
The product of [3, 7] is 21

Example Output 3
Enter number 1: 0
Enter number 2: 5
Enter number 3: 10
Enter number 4: 15
Enter number 5: 20
The product of [10, 20] is 200
The product of [5, 15] is 75

Example Output 4
Enter number 1: 3
Enter number 2: -6
Enter number 3: -4
Enter number 4: 8
Enter number 5: 2
The product of [8, 2] is 16
The product of [3] is 3

Answer 1

由于 OP 似乎被分配了作业，这是一个略有不同的解决方案，未使用所需的 forEach():

val numbers = mutableListOf<Int>()

while (true) {
  print("Enter number ${numbers.count() + 1}: ")
  val input = readln()
  if (input.trim() == "" || input.toIntOrNull() == null) continue
  numbers.add(input.toInt())
  if (numbers.count() == 5) break
}

val evens = numbers.filter { it > 0 && it % 2 == 0 }
val odds = numbers.filter { it > 0 && it % 2 != 0 }

val productOfEvens = evens.reduce { acc, i -> acc * i }
val productOfOdds = odds.reduce { acc, i -> acc * i }

println("The product of $evens is $productOfEvens")
println("The product of $odds is $productOfOdds")

如何使用 Kotlin lambda 表达式求奇数和偶数的乘积

How to find product of odd and even numbers using Kotlin lambda expression

lambda

function

kotlin