Question

我已经开始学习java并且正在为这种练习编写代码。请告诉我哪里出错了，它说我在第27行有一个非法的表达。

import java.util.Scanner;
public class steps
{
    public static void main(String []args)
    {
        Scanner Keyboard =  new Scanner(System.in);
        print("What is your name?");
        String name = Keyboard.nextLine();
        print("What is five + five?");
        String number = Keyboard.nextLine();
        String gj = (", Good Job");

        switch (number){
            case "ten":
                print("correct" + gj + (" ") + name);
                break;
            case "Ten":
                print("correct" + gj +(" ") + name);
                break;
            case "10":
                print("correct" + gj +(" ") + name);
                break;
            default:
                print("Wroung try again");
        }

        static void print(String s) {  // <--- this is line 27
            System.out.println(s);
        }
    }
// <--- there is no trailing } here?

Answer 1

您无法在Java中的方法内定义方法，请将此代码移出main()方法：

 static void print(String s){
      System.out.println(s);
  }

仔细看看你的大括号，这是明确的代码缩进有用的地方。

Answer 2

计算您的开始和结束花括号 - 您已经关闭。您缺少一个右大括号，因此，看起来您在另一个方法中声明了一个方法。

Answer 3

java中不允许使用嵌套方法。嵌套方法表示另一个方法中的方法。在您的情况下，print方法包含在main中方法是不允许的。

喜欢这个

import java.util.Scanner;
public class steps
{
    public static void main(String []args)
    {
         Scanner Keyboard =  new Scanner(System.in);
        print("What is your name?");
        String name = Keyboard.nextLine();
          print("What is five + five?");
        String number = Keyboard.nextLine();
        String gj = (", Good Job");

      switch (number){
          case "ten":
              print("correct" + gj + (" ") + name);
              break;
          case "Ten":
              print("correct" + gj +(" ") + name);
              break;
          case "10":
              print("correct" + gj +(" ") + name);
              break;
          default:
              print("Wroung try again");
      }


   }
    static void print(String s){
        System.out.println(s);
    }
}

Answer 4

可能你的意思是在第27行之前还有一个结束大括号，这样static void print(String s)就不会里面 {{1} }

Answer 5

Static不会也不应该进入main。你可以像调用print("String printed");

一样调用main中的print方法

import java.util.Scanner;

public class steps {

public static void main(String[] args) {
    Scanner Keyboard = new Scanner(System.in);
    System.out.print("What is your name? ");
    String name = Keyboard.nextLine();
    System.out.print("What is five + five? ");
    String number = Keyboard.nextLine();
    String gj = (", Good Job");

    switch (number) {
    case "ten":
        System.out.print("correct" + gj + (" ") + name);
        break;
    case "Ten":
        System.out.print("correct" + gj + (" ") + name);
        break;
    case "10":
        System.out.print("correct" + gj + (" ") + name);
        break;
    default:
        while (Integer.parseInt(number)!= 10){//Checks if number isn't correct
            //and ask user to input again until he gets it right.
        System.out.print("Wrong try again :");
         number = Keyboard.nextLine();
         if(Integer.parseInt(number)==10){
                System.out.print("correct" + gj + (" ") + name)

         }

        }
    }
    print("String printed");

}

static void print(String s) { 
    System.out.println("\n"+s);
   }
}

为什么这个初学java程序有错误

5 个答案: