分配拳击重量等级

Question

我在写的JavaScript 中遇到问题。该脚本假设提示用户输入重量，从 0 到 126，然后弹出一个警告框，说明他们所处的重量。

weight class      from    to
-------------------------------
Fly               0     112
SuperFly          112   115
Bantam            115   118
SuperBantam       118   122
Feather           122   126

<script type="text/javascript">
  var weight = parseInt(prompt("What is your weight?"));
  if (weight > 126) {
    alert('Please enter a weight lighter than 126');
  }
  document.writeln('<br/>');
  var wArray = String ([fly,superfly,bantam,superbantam,feather]);

  function recruit() {
    if (0 < weight < 112){
      document.writeln('You are in' + wArray[0] +'class!');
    }
    if (112 < weight < 115){
     document.writeln('You are in' + wArray[1] +'class!');
    }
    if (115 < weight < 118){
      document.writeln('You are in' + wArray[2] +'class!');
    }
    if (118 < weight < 122){
      document.writeln('You are in' + wArray[3] +'class!');
    }
    if (122 < weight 126){
      document.writeln('Your weight class is' + wArray[4]);
    }

</script>

Answer 1

改变这个

var wArray = String ([fly,superfly,bantam,superbantam,feather]);

到这里

var wArray = ["fly", "superfly", "bantam", "superbantam", "feather"];

JavaScript 中的所有数组都是动态类型的。没有办法创建字符串数组；您只需创建一个数组并用字符串填充它。

还有，

if (115 < weight < 118)

无效。你想要的

if (weight > 115 && weight < 118)

Answer 2

这是重写代码的第一步：

var weight = prompt("What is your weight?") * 1;
if (weight>126){
  alert('Please enter a weight lighter than 126');
}else if (weight > 122){
  alert('You are in' + wArray[4] +'class!');
}else if (weight > 118){
  alert('You are in' + wArray[3] +'class!');
}else if (weight > 115){
  alert('You are in' + wArray[2] +'class!');
}else if (weight > 112){
  alert('You are in' + wArray[1] +'class!');
}else{
  alert('You are in' + wArray[0] +'class!');
}

现在，看看这个并考虑如何编写一个for 循环，并创建一个将限制与名称配对的数据结构。然后你可以循环遍历你的数组，直到找到正确的条目。

提示：这个呢

var classes = [
  { min:123, max:126, name:'fly'      },
  { min:119, max:122, name:'superfly' },
  // etc.
];