java - for循环: cannot find symbol error

Question

    public class javapractice14
{
  public static void main(String[] args)
  {
    int largest = Integer.MIN_VALUE;
    int smallest = Integer.MAX_VALUE;

    Scanner console = new Scanner(System.in);
    System.out.println("Please enter desired amount of numbers (-1 ends program)");
    for( int number = console.nextInt(); number != -1; number = console.nextInt()); //Enter -1 to end program
    {

我收到以下错误消息，说找不到符号:变量号

我相信number是在for循环中声明的，不是在那儿声明的吗？我试过在循环外声明“ int number; ”，但结果相同。我使用: What do I have to do to display the largest and the smallest number using a loop?作为帮助我解决部分问题的引用。

      largest = number > largest ? number : largest;
      smallest = number < smallest ? number : smallest;
    }
    System.out.println("Your largest number is: " + largest);
    System.out.println("You smallest number is: " + smallest);
    }
}

Answer 1

for( int number = console.nextInt(); number != -1; number = console.nextInt()); <-看到for循环的末尾有分号，这意味着循环从此处结束
因此，您不能从循环外部引用在for循环内部声明的块变量。这就是为什么会出现该编译错误的原因

删除该分号。那它一定能正常工作

for( int number = console.nextInt(); number != -1; number = console.nextInt()){ // no semicol at the end
      // your logic
}
// print your numbers