无法退出do while循环，即使表达式为false

Question

import java.util.*;
public class number_guassing_game{
    private static int a = 0;
    public static void main(String[] args) {
       Scanner in=new Scanner(System.in);
       int number=(int)(Math.random()*100+1);
       int count=0;
       boolean flag = true;
       do {
           int a = in.nextInt();
           count+=1;
           if(a>number) {
               System.out.println("smaller!");
           }else if(a<number) {
               System.out.println("bigger!");
           }
        }while(a != number); 
        System.out.println("congratulations!"+" You have guessed "+count+" times!");
    }
}

Obviously the answer is 48, but it didn't the loop and print the expression.

Answer 1

The loops condition

while(a != number);

doesn't see the local variable into which you read the input:

int a = in.nextInt();

It sees the static variable initialized to 0 that never changes:

private static int a = 0;

Therefore the loop never terminates.

You should change

int a = in.nextInt();

to

a = in.nextInt();

Oh, and there's no reason for a to be static . It could be a local variable of the main method, as long as it is declared outside (and before) the loop.

Answer 2

The a you define inside the loop shadows the a from outside it. That a is never updated, and thus the loop will only be terminated if you enter 0 (the original value a was initialized with). In order to avoid this, just use the same a instead of declaring a new variable:

a = in.nextInt(); // no datatype here, since you aren't defining a new variable