Output is right but all test are wrong why

#1

import java.util.*;
public class Main {
public static void main(String args[]) {
Scanner scan = new Scanner(System.in);

    char ch = scan.next().charAt(0);
    while(ch == '+' || ch == '-' || ch == '*' || ch == '/' || ch == '%' || ch == ';') {
        
        int c = 0;
        if(ch=='+') {
            int a = scan.nextInt();
            int b = scan.nextInt();
            c=a+b;
            System.out.println(c);
        }
        else if(ch=='-') {
            int a = scan.nextInt();
            int b = scan.nextInt();
            c=a-b;
            System.out.println(c);
        }
        else if(ch=='*') {
            int a = scan.nextInt();
            int b = scan.nextInt();
            c=a*b;
            System.out.println(c);
        }
        else if(ch=='%') {

            int a = scan.nextInt();
            int b = scan.nextInt();
            if(b != 0)
                c=a%b;
            System.out.println(c);
        }
        else if(ch=='/') {
            int a = scan.nextInt();
            int b = scan.nextInt();
            if(b != 0)
                c=a/b;
            System.out.println(c);
        }
        else
            System.out.println("Invalid operation. Try again.");
        ch = scan.next().charAt(0);
            
    }
    
}

}

#2

hey @himanshusingh2389_63aac7fac0c69386 Your code is not printing anything for the input
.
?
/
4
2
*
4
2
x
To cure this you should use do while loop .
This might help

import java.util.Scanner;
public class main{
   static Scanner scn=new Scanner(System.in);
    public static void main(String[] args) {
        char ch;
        do {
            ch = scn.next().charAt(0);  // Use cin in case of c++
            if (ch == '+' || ch == '-' || ch == ' * ' || ch == '/' || ch == '%') {
                operation(ch);
            } else {
                if (ch != 'x' && ch != 'X')
                    System.out.println("Invalid operation. Try again.");
            }
        } while (ch != 'x' && ch != 'X');
    }
    public static void operation(char ch) {
        int a = scn.nextInt(); // Use cin in case of c++
        int b = scn.nextInt(); // Use cin in case of c++
        int res = 0;
        switch (ch) {
        case '+': {
            res = a + b;
            break;
        }
        case '-': {
            res = a - b;
            break;
        }
        case '*': {
            res = a * b;
            break;
        }
        case '/': {
            res = a / b;
            break;
        }
        case '%': {
            res = a % b;
            break;
        }
        }
        System.out.println(res);
    }
}
#3

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