我的代码无法运行，但没有错误

Question

I have two questions:

1. Why won't my program run?
2. How can i make it check if the input isn't equal to some something?

--

import java.util.Random;
import java.util.Scanner;

public class HeigherOrLower {

        //Creates the scanner.
    static Scanner sc = new Scanner(System.in);
    static String input = sc.nextLine();

    public static void main(String[] args)
    {
        //Creating the two random numbers.
        Random rand = new Random();
        int userNumber  = rand.nextInt(10) + 1;
        int comNumber = rand.nextInt(10) + 1;

        System.out.println("Your number is: " + userNumber +" of 10");
        System.out.println("Do you think that your number is Heigher(H), Lower(L) or Equal To(E) the computers number");

            //Checking if the user is right.
        if(userNumber < comNumber && input.equals("L"))
            System.out.println("You are right. The computer's number is: " + comNumber);

        if(userNumber == comNumber && input.equals("E"))
            System.out.println("You are right. The computer's number is: " + comNumber);

        if(userNumber > comNumber && input.equals("H"))
                System.out.println("You are right. The computer's number is: " + comNumber);
    }
}

Answer 1

It will run and wait for user input at

static String input = sc.nextLine();

I think you are not able to observe the console while you run it in eclipse. See if the java process is present in the process list

Answer 2

It runs fine for me, but it waits for user input before it outputs any text. You might want to move your two static lines into the main method after the "Do you think..." line:

import java.util.Random;
import java.util.Scanner;


public class HeigherOrLower
{

    public static void main(String[] args)
    {
        //Creating the two random numbers.
        Random rand = new Random();
        int userNumber  = rand.nextInt(10) + 1;
        int comNumber = rand.nextInt(10) + 1;

        System.out.println("Your number is: " + userNumber +" of 10");
        System.out.println("Do you think that your number is Heigher(H), Lower(L) or Equal To(E) the computers number");

        //Creates the scanner.
        Scanner sc = new Scanner(System.in);
        String input = sc.nextLine();

        //Checking if the user is right.
        if(userNumber < comNumber && input.equals("L"))
            System.out.println("You are right. The computer's number is: " + comNumber);

        if(userNumber == comNumber && input.equals("E"))
            System.out.println("You are right. The computer's number is: " + comNumber);

        if(userNumber > comNumber && input.equals("H"))
            System.out.println("You are right. The computer's number is: " + comNumber);
    }
}

static initializers are executed before the main method. So, it's waiting for input before anything is being output, giving the impression that nothing is happening.

To check if a string value is not equal, use the not operator "!" as shown here:

if ( ! input.equals("H") ) 

For numeric values, just use != as shown here:

if ( x != 3 )

Answer 3

Your program does"RUN" it is just you don't have any prmpots==>> System.out.println("Please tyoe your input") /// Or any other sort of prompt messages to notify the user. As for your Scanner , I removed the invalid modifier "Static" and moved to inside your MAIN class.As for the logic I am not sure what its supposed to be doing.

     public class HeigherOrLower {

    //Creates the scanner.


    public static void main(String[] args)
     {

        System.out.println("Please type your input");
        Scanner sc = new Scanner(System.in);
        String input = sc.nextLine();
    //Creating the two random numbers.
    Random rand = new Random();
    int userNumber  = rand.nextInt(10) + 1;
    int comNumber = rand.nextInt(10) + 1;

    System.out.println("Your number is: " + userNumber +" of 10");
    System.out.println("Do you think that your number is Heigher(H), Lower(L) or Equal To(E) the computers number");

        //Checking if the user is right.
    if(userNumber < comNumber && input.equals("L"))
        System.out.println("You are right. The computer's number is: " + comNumber);

    if(userNumber == comNumber && input.equals("E"))
        System.out.println("You are right. The computer's number is: " + comNumber);

    if(userNumber > comNumber && input.equals("H"))
            System.out.println("You are right. The computer's number is: " + comNumber);




      }
    }

Answer 4

These two lines:

static Scanner sc = new Scanner(System.in);
static String input = sc.nextLine();

Do the following:

• Construct a new Scanner that uses the standard input
• Read the first line from the Scanner

Since this is not declared inside a method, this happens pretty much right when you run the program (I won't confuse you with the technicalities).

So it's waiting to read the input before it outputs anything.

So you perhaps want to put those two statements, with static removed, inside the main method, perhaps after this line:

System.out.println("Do you think that your number is Heigher(H), Lower(L) or Equal To(E) the computers number");

If this is not the problem, you're indeed probably not running it at all, and you'll have to provide more details as to how you're trying to run it.

To check if your input isn't equal to something, you can either just say !input.equals("something") (inside an if-statement, the ! here means "not"), or you can use else :

if (input.equals("something"))
   System.out.println("It's equal");
else
   System.out.println("It's not equal");

Answer 5

您能否检查一下您是否将文件命名为 HeigherOrLower.java，否则对其进行适当的重命名，谢谢！