Question

这是Java，我正在使用TextWrangler。我收到了几个错误，包括'else'没有'if'错误，无法找出原因。我还不得不拿出“公共课税”{ public static void main（String [] args）{“因为它告诉我他们没有正确编码。我得到的错误的一些例子包括：

Tax.java:85: error: 'else' without 'if'
        else(taxable <= 186475)

Tax.java:85: error: ';' expected
        else(taxable <= 186475)
                               ^

Tax.java:85: error: not a statement
        else(taxable <= 186475)
            ^

import java.util.Scanner;


    java.util.Scanner input = new java.util.Scanner(System.in);

    double tax;

    System.out.print("Please enter filing status: ");
    int status = input.nextInt();

    System.out.println("Please enter taxable income: ");
    double taxable = input.nextDouble();

    if(status == 0){
        if(taxable <= 8350)
            tax = taxable * .10;
            System.out.println("Tax is " + tax);    
        else if(33950 >= taxable && taxable >= 8351)
            taxable = taxable - 8350;
            tax = taxable * .15 + 8350 * .10;
            System.out.println("Tax is " + tax);
        else if(82250 >= taxable && taxable >= 33951)
            taxable = taxable - 33950 - 8350;
            tax = taxable * .25 + 33950 * .15 + 8350 * .10;
            System.out.println("Tax is " + tax);
        else if(171550 >= taxable && taxable >= 82251)
            taxable = taxable - 82250 - 33950 - 8350;
            tax = taxable * .28 + 82250 * .25 + 33950 * .15 + 8350 * .10;
            System.out.println("Tax is " + tax);
        else if(372950 >= taxable && taxable >= 171551)
            taxable = taxable - 171550 - 82250 - 33950 - 8350;
            tax = taxable * .33 + 171550 * .28 + 82250 * .25 + 33950 * .15 + 8350 * .10;
            System.out.println("Tax is " + tax);
        else(taxable <= 372951)
            taxable = taxable - 372950 - 171550 - 82250 - 33950 - 8350;
            tax = taxable * .35 + 372950 * .33 + 171550 * .28 + 82250 * .25 + 33950 * .15 + 8350 * .10;
            System.out.println("Tax is " + tax);
        }

Answer 1

始终用花括号括起所有代码块，尤其是在开始时，包括所有if块，所有循环，所有控制结构。

你错误的缩进是在愚弄你让你认为if块只包含一行代码时包含3行代码。

你看到了：

    if (taxable <= 8350)
        tax = taxable * .10;
        System.out.println("Tax is " + tax);    
    else if(33950 >= taxable && taxable >= 8351)
        taxable = taxable - 8350;
        tax = taxable * .15 + 8350 * .10;
        System.out.println("Tax is " + tax);

真的相当于：

    if (taxable <= 8350) {
        tax = taxable * .10;
    }

    System.out.println("Tax is " + tax);    

    // you've got a hanging else here
    else if(33950 >= taxable && taxable >= 8351) {
        taxable = taxable - 8350;
    }

    tax = taxable * .15 + 8350 * .10;
    System.out.println("Tax is " + tax);

    // and more hanging else's below...

所以改成它：

    if (taxable <= 8350) {
        tax = taxable * .10;
        System.out.println("Tax is " + tax);    
    }  else if(33950 >= taxable && taxable >= 8351) {
        taxable = taxable - 8350;
        tax = taxable * .15 + 8350 * .10;
        System.out.println("Tax is " + tax);
    } //.... and continue similarly throughout your program

Answer 2

你需要在'then'子句中加上大括号。例如：

if(taxable <= 8350) {
        tax = taxable * .10;
        System.out.println("Tax is " + tax);    
}
else  .....

Answer 3

如果你有if-else的多个语句，那么请使用大括号。最好总是使用牙箍。

表格Doc

块是平衡大括号之间的一组零个或多个语句，可以在允许单个语句的任何位置使用。以下示例BlockDemo说明了块的使用。

写如下：

   if(status == 0){
        if(taxable <= 8350){
            tax = taxable * .10;
            System.out.println("Tax is " + tax);    
         }
        else if(33950 >= taxable && taxable >= 8351){
            taxable = taxable - 8350;
            tax = taxable * .15 + 8350 * .10;
            System.out.println("Tax is " + tax);
         }

 ....
        }

Answer 4

您需要为if添加花括号。

if(taxable <= 8350){
            tax = taxable * .10;
            System.out.println("Tax is " + tax);    
        }else if(33950 >= taxable && taxable >= 8351){
            taxable = taxable - 8350;
            tax = taxable * .15 + 8350 * .10;
            System.out.println("Tax is " + tax);
        }

否则，它只是第一行在if

中

Answer 5

因为你的if语句没有用{}的

括起来

这意味着只有下一行在if语句下计数。以下行在if语句之外执行，然后“else”语句放置时没有if。

Answer 6

如果IF或ELSE的主体跨越多个语句，则需要使用花括号。

没有'if'错误就得到'else'，不知道为什么

6 个答案: