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我一直在学习 java 课程http://www.programmingbydoing.com，但我被困在其中一项作业上，我可以得到一些帮助吗？我的代码在这里：http ://pastebin.com/raw.php?i=Si49CbN9

public static void main( String[] args )
{
    Scanner keyboard = new Scanner ( System.in );
    int age;
    String name;

    System.out.println( "What is your name" );
    name = keyboard.next();

    System.out.println( "So " + name + "how old are you? ")
    age = keyboard.nextInt();

    if ( age < 16 );
    {
        System.out.println( "You cant drive");
    }

    else ( age <= 17 );
    {
        System.out.println( "You can drive, but not vote." );
    }

    else ( age <= 24 );
    {
        System.out.println( "You can vote but not rent a car" );
    }

    else if
    {
        System.out.println( "You can do pretty much anything" );
    }
}

任务是： 使用 if 语句、else if 和 else 语句，制作一个根据给定年龄显示不同消息的程序。

年龄小于 16 的消息“你不能开车。” 16 至 17 “你可以开车但不能投票。” 18 到 24 “你可以投票但不能租车。” 25 岁或以上 “你几乎可以做任何事情。”

请注意，与最初的“你多大了”作业不同，该程序必须只显示给定年龄的一条消息，而不是多条消息。

4

6 回答 6

3

多个问题

if ( age < 16 ) {   //SEE NO ; here. ; makes end of statement 
    System.out.println( "You cant drive");
}
else if( age <= 17 ) {
   //something else
}
于 2013-07-25T09:19:00.233 回答
1

看起来您已经交换了“else”和“else if”语句。“else”语句不应该采用“else if”语句应该的条件。也没有“;” 条件后。即它应该是：

if (age < 16) {
...
} else if (age <= 17 ) {
...
} else {
...
}
于 2013-07-25T09:23:59.357 回答
0 
if(age>24) {
     {
            System.out.println( "You can do pretty much anything" );
        }

}
 if( age >= 17 && age<=24 )
{
    System.out.println( "You can vote but not rent a car" );
}

if( age <= 17 && age>=16 )
 {
System.out.println( "You can drive, but not vote." );
}
 if ( age<16 )
  {
     System.out.println( "You cant drive");
   }
于 2013-07-25T09:24:30.317 回答
0

语法错误。不能将条件语句附加到关键字else。请参考以下代码：

if ( age < 16 )
    {
        System.out.println( "You cant drive");
    }

    else if( age <= 17 )
    {
        System.out.println( "You can drive, but not vote." );
    }

    else if ( age <= 24 )
    {
        System.out.println( "You can vote but not rent a car" );
    }

    else
    {
        System.out.println( "You can do pretty much anything" );
    }
于 2013-07-25T09:24:33.720 回答
0

您有语法错误。

请试试：

if ( age < 16 )
{
    System.out.println( "You cant drive");
}
else if ( age <= 17 )
{
    System.out.println( "You can drive, but not vote." );
}
else if ( age <= 24 )
{
    System.out.println( "You can vote but not rent a car" );
}
else 
{
    System.out.println( "You can do pretty much anything" );
}

你可以在这里学习 if/then/else 语句

于 2013-07-25T09:17:35.963 回答
0

尝试这个，

  if (age < 16){
        System.out.println( "You cant drive");
    } else if (age <= 17) {
        System.out.println( "You can drive, but not vote." );
    } else if (age <= 24) {
        System.out.println( "You can vote but not rent a car" );
    } else {
        System.out.println("You can do pretty much anything");
    }

删除所有if 条件中的分号

于 2013-07-25T09:20:09.370 回答