Kotlin石头剪刀布游戏异常：电脑每次获胜求代码排查

• 核心问题：computerChoice变量未正确赋值
  你初始化了val computerChoice = ""，但在生成随机数确定电脑出拳时，只通过println打印了电脑的选择，却没有把对应的值赋值给computerChoice。这导致computerChoice始终是空字符串，永远无法匹配玩家获胜的条件（比如playerChoice == "Rock" && computerChoice == "Scissor"），最终所有情况都会走到else -> "Computer"分支，所以电脑每次都赢。

修复后的代码 #

package com.blinky.kotlinbasics

fun main() {
    var computerChoice = "" // 改为var，方便后续赋值
    var playerChoice = ""
    println("Rock, Paper or Scissor? Enter your choice!")
    playerChoice = readln()

    val randomNumber = (1..3).random()
    if(randomNumber == 1){
        computerChoice = "Rock" // 给computerChoice赋值
        println("Rock")
    }
    else if(randomNumber == 2){
        computerChoice = "Paper" // 给computerChoice赋值
        println("Paper")
    }
    else if(randomNumber == 3){
        computerChoice = "Scissor" // 给computerChoice赋值
        println("Scissor")
    }

    val winner = when{
        playerChoice.equals(computerChoice, ignoreCase = true) -> "Tie" // 支持大小写不敏感输入
        playerChoice == "Rock" && computerChoice == "Scissor" -> "Player"
        playerChoice == "Paper" && computerChoice == "Rock" -> "Player"
        playerChoice == "Scissor" && computerChoice == "Paper" -> "Player"
        else -> "Computer"
    }
    if(winner == "Tie"){
        println("The game is a tie")
    }
    else{
        println("$winner won!") // 用字符串模板简化输出
    }
}

关键修改说明 #

1. 将val computerChoice = ""改为var computerChoice = ""：因为需要后续修改该变量的值，val是不可变变量，无法重新赋值
2. 在每个随机数分支中添加computerChoice = "XXX"：让变量真正存储电脑的出拳结果，才能和玩家的选择进行胜负判断
3. 可选优化：用equals(ignoreCase = true)判断平局，允许玩家输入大小写不敏感的内容（比如输入"rock"也能正常匹配），提升用户体验

内容的提问来源于stack exchange，提问作者Blinky