Question

当使用其中一个for循环时，我需要打破if语句。但是当我编译并运行它时，当我只需要一个时，所有三个for循环都会返回信息。我知道答案是盯着我看，但我无法弄清楚它是什么。

if (filestat == 'S' || filestat == 's')
{

  for ( a = 0; a < 5000; a++)
  {
     taxableincome = grossincome - 5000 - (1000 * exemptions);
     taxrate = .15;
     taxAmount = taxableincome * taxrate;
     System.out.println("Your Taxpayer ID is " + taxid);
     System.out.println("Your taxable income is $" + taxableincome);
     System.out.println("Your tax rate is %" + taxrate);
     System.out.println("Your tax amount is $" + taxAmount);

     break;
  }

  for (a = 5000; a <= 20000; a++)
  {
     taxableincome = grossincome - 5000 - (1000 * exemptions);
     taxrate = .22;
     taxAmount = taxableincome * taxrate;
     System.out.println("Your Taxpayer ID is " + taxid);
     System.out.println("Your taxable income is $" + taxableincome);
     System.out.println("Your tax rate is %" + taxrate);
     System.out.println("Your tax amount is $" + taxAmount);

     break;
  }

  for (a = 20001; a >= 20001; a++)
  {
     taxableincome = grossincome - 5000 - (1000 * exemptions);
     taxrate = .31;
     taxAmount = taxableincome * taxrate;
     System.out.println("Your Taxpayer ID is " + taxid);
     System.out.println("Your taxable income is $" + taxableincome);
     System.out.println("Your tax rate is %" + taxrate);
     System.out.println("Your tax amount is $" + taxAmount);

     break;
  }

}

Answer 1

如果要打印所有可能a的输出，只需删除break语句即可。（但是你必须为第三个循环提供一个上限。）

如果您只想为一个特定a打印输出，则应使用if代替for。

if (filestat == 'S' || filestat == 's')
{
    if (a < 5000)
    {
        taxableincome = grossincome - 5000 - (1000 * exemptions);
        taxrate = .15;
        taxAmount = taxableincome * taxrate;
    }
    else if (a <= 20000)
    {
        taxableincome = grossincome - 5000 - (1000 * exemptions);
        taxrate = .22;
        taxAmount = taxableincome * taxrate;
    }
    else
    {
        taxableincome = grossincome - 5000 - (1000 * exemptions);
        taxrate = .31;
        taxAmount = taxableincome * taxrate;
    }
}
System.out.println("Your Taxpayer ID is " + taxid);
System.out.println("Your taxable income is $" + taxableincome);
System.out.println("Your tax rate is %" + taxrate);
System.out.println("Your tax amount is $" + taxAmount);

Answer 2

当使用其中一个for循环时，我需要打破if语句。

这根本没有意义。因为在if语句中，所有循环至少无条件地运行一次（无论break语句都没有意义），你不能指望Java神奇地“选择”其中一个循环。

如果您不想运行后两者，为什么不删除它们呢？

Answer 3

我猜你试图根据a的值进行计算，你可以使用嵌套的if-else语句而不是使用循环并在第一次迭代时将其分解。

    `if (filestat == 'S' || filestat == 's')
    {
      if( a >= 0 && a < 5000 )
        //do some work
      else if( a >= 5000 && a <= 20000 )
      //do some work
      else if( a > 20000)
     //do some work 
    }`

您可以选择将代码包装在函数中并将税率作为参数传递，因为它是唯一取决于a的值的变量。

如果我打破这个怎么办？

3 个答案: