Question

我想将“numberOfItems”设置为一个大数字但是想要在中途停止循环。我需要帮助的部分时间。请不要ArrayList，我还不熟悉。

$(".pin-input").keyup(function () {
  this.value = this.value.replace(/[^0-9\.]/g,'');

  if (this.value.length == this.maxLength) {
    var $next = $(this).parent().next('.input-container').find('.pin-input');

    if ($next.length) {
      $next.focus();
    }
    else {
      $(this).blur();
    }
  }
});

$('button.show-password').each(function(){
  var selected_container = $(this).data("container"); // Get button container value
  var selected_input = $(selected_container).find("input"); // Selected input withing container
  var selected_icon = $(this).find('i');

  $(this).mousedown(function(){
    $(this).toggleClass('active');
    $(this).attr('value', 'Hide');
    selected_input.attr('type', 'text');

    if(selected_icon.length > 0) {
      selected_icon.toggleClass('icon-show-password');
    }
    else {
      $(this).text("Hide");
    }
  }).mouseup(function(){
    $(this).toggleClass('active');
    $(this).attr('value', 'Show');
    selected_input.attr('type', 'password');

    if(selected_icon.length > 0) {
     selected_icon.toggleClass('icon-show-password');
    }
    else {
     $(this).text("Show");
    }
  });
});

Answer 1

您可以在if循环内放置for语句，以决定何时停止它;停止循环的指令是break。

请注意，这意味着您不需要封闭的do循环。

Answer 2

查看您的代码是如何工作的，最明智的地方可能是在输入产品名称之后。这意味着您无法存储STOP产品......我将其保留为大写（如果您不关心案例，可以使用equalsIgnoreCase。）

这样的事情：

    for(int i=0; i<=numberOfItems; i++)
    {
       System.out.println("Enter product name (or STOP to stop)");
       String tmpProduct = input.nextLine();

       //trim to avoid whitespace
       if ("STOP".equals(tmpProduct.trim())) {
          break; //we stop the loop here
       }

       //they didn't type STOP, guess they wanted a product.
       productName[i]=tmpProduct;


       System.out.println("Enter price of product");
       productPrice[i]=input.nextDouble();
       System.out.printf("%s,%n,%.2f",productName[i],productPrice[i]);
    }

这也避免了对外环的需要。如果您更愿意在每件产品之后询问（这可能会在一段时间后变得烦人），那么您可以在请求双倍后进行检查和提示。

    for(int i=0; i<=numberOfItems; i++)
    {
       System.out.println("Enter product name");

       //they didn't type STOP, guess they wanted a product.
       productName[i]=input.nextLine();

       System.out.println("Enter price of product");
       productPrice[i]=input.nextDouble();
       System.out.printf("%s,%n,%.2f",productName[i],productPrice[i]);

       System.out.println("type STOP to stop or anything else to continue");
       String tmp = input.nextLine();
       //trim to avoid whitespace problems
       if ("STOP".equals(tmp.trim())) {
          break; //we stop the loop here
       }
    }

Answer 3

更新这是详细解释的增强型答案

// this method to validate the input after reading the entire line
static public Object interpretedInput(String line){
   if(line.replace(" ", "").equalsIgnoreCase("stop")){ // if stop detected 
      return null; 
   }
   else {// if it's not stop
       for(char c : line.toCharArray()){ // read every char in the line
           if(!Character.isDigit(c) && c!='.'){ // if any non digit is detected that means it should be considered as a string 
              //(note if you want the product name to consist of digits only -> this won't work)
              return line; // return line
          }
      }
   }
   try{return Double.valueOf(line);} // else try to parse the line to extract the double value and return it
   catch(NumberFormatException e){return null;}
}


Scanner input = new Scanner(System.in);
int numberOfItems = 10; // for example
String[]productName = new String[10];
double[] productPrice = new double[10];
for(int i=0; i<numberOfItems; i++){
    System.out.println("Enter product name");
    Object theInput = interpretedInput(input.nextLine()); // the method will return either null or string or double 
    if(theInput==null){ // if it's null that means to stop
         break;
    }
    else if (theInput instanceof String){ // if it's instance of string accept it 
            productName[i]=(String)theInput;
    }
    while(!(theInput instanceof Double)){ // this will repeat until a valid double input is entered 
         //then it will assign it and display the content
         System.out.println("Enter price of product");
         theInput = interpretedInput(input.nextLine());
         if(theInput==null){
              i=numberOfItems; // to terminate the parent for loop as well
                break;
         }
         else if (theInput instanceof Double){
             productPrice[i]=(Double)theInput;
             System.out.printf("%s, %.2f\n",productName[i],productPrice[i]);
         }
         else{System.out.println("Invalid Price");}
    }
}

如何使用“stop”作为关键字来停止for循环？

3 个答案: