Question

在下面的代码中，当我将userDoor变量设置为提示的用户输入时，用户输入附加到变量。我知道这一点，因为该值显示在变量声明正下方的console.log语句中。

然而，变量revealDoor和offerDoor是基于userInput变量设置的，它们表示变量没有“捕捉”＃34;价值。（ Wonky ：比说明更容易演示。请运行下面的代码.UserDoor，revealDoor和offerDoor都应该是1-3范围内的不同数字。有些时候，revealDoor === userDoor。这绝不会发生。）。

有趣的是，当我将userDoor直接设置为整数时，程序运行正常 - 请参阅注释调试行。

为什么 userInput变量会在控制台中显示正确的值，但似乎没有捕获到程序的其余部分？

（顺便说一下，这个程序是为了说明monty hall paradox

＆＃13;

alert("There are 3 doors.  Behind two of them are DEATH and DOOM.  Behind the other is a BIG TASTY SAUSAGE.");

var yWin = 0;
var yLoss = 0;
var nWin = 0;
var nLoss = 0;


while(true){ //noprotect
  var userDoor = prompt("choose door: 1, 2, or 3");
  //var userDoor = 1 //debug
  console.log('UD: ' + userDoor);


  

  var prizeDoor = randomRange(1,3);
  console.log('PD: ' + prizeDoor);

  var revealDoor = (function(){
    var revealDoor = prizeDoor;
    if (prizeDoor === userDoor) {
      while (revealDoor === prizeDoor) {
        revealDoor = randomRange(1,3);
      }
      return revealDoor;
    }
    else {
      while (revealDoor === prizeDoor || revealDoor === userDoor){
        revealDoor = randomRange(1,3); 
      }
      return revealDoor;
    }
  })();
  console.log('RD: ' + revealDoor);

  var offerDoor = (function(){
    var offerDoor = prizeDoor;
    while(offerDoor === revealDoor || offerDoor === userDoor){
      offerDoor = randomRange(1,3);
    }
    return offerDoor;
  })();
  console.log('OD: ' + offerDoor);

  var choice = prompt("You chose door " + userDoor + ".  Behind door " + revealDoor + ", I reveal DEATH AND DOOM.  I would like to offer you the chance to change your choice to " + offerDoor + ".  Do you accept--y/n?");

  if(choice === "y"){
    userDoor = offerDoor;
  }
  
  var result = (function(){
    var result;
    if(userDoor === prizeDoor){
      alert("YOU FOUND THE PRIZE!");
      result = 'w';
    }
    else {
      alert("You chose DEATH AND DOOM!");
      result = 'l';
    }
    return result;
  })();
  
  
  //Analytics:
  
  switch(result){
    case 'w':
      if(choice === 'y'){
        yWin++;
      }
      else {
        nWin++;
      }
      break;
    case 'l':
      if(choice === 'y'){
        yLoss++;
      }
      else {
        nLoss++;
      }
      break;
  }
             
  var done = prompt("Are you Done?  y/n");
  if(done === "y"){
    break;
  }

}


function randomRange(min, max) {
  return Math.floor(Math.random () * (max - min +1)) + 1;
}

var totalSamples = yWin + nWin + yLoss + nLoss;
var yChoices = yWin + yLoss;
var nChoices = nWin + nLoss;
  
console.log('With a sample set of ' + totalSamples);
console.log('You chose to change ' + (yChoices/nChoices * 100) + '% of the time.');
console.log('When you\'ve chosen to change, you\'ve won ' + (yWin/yChoices * 100) + '% of the time.');
console.log('When you\'ve chosen to stay, you\'ve won ' + (nWin/nChoices * 100) + '% of the time.');

＆＃13;

Answer 1

var userDoor = prompt("choose door: 1,2,       or 3")) * 1

这个

更好用2个单选按钮

Answer 2

问题是prompt（）返回一个字符串。这意味着任何＆＃39; ===＆＃39;比较返回undefined。我需要使用Number()将返回的字符串转换为数字。

var userDoor = Number(prompt("choose door: 1,2, or 3"))

Answer 3

使用

var done = confirm("Are you Done?  y/n");
if (done) break;

而不是d提示确认

如何将变量设置为从提示返回的值（＆＃39; ...＆＃39;）？

3 个答案: