While Loop Exercises

import java.util.Scanner;

public class WhileLoop {
    public static void main(String[] args) {
        //-------------------Ex1---------------------

        Scanner sc = new Scanner(System.in);
        int num, counter = 0;
        while(counter < 5) {
            System.out.println("Please enter a number: ");
            num = sc.nextInt();
            if(num % 2 == 0) counter+=1;
        }

        //----------------Ex2---------------------------

        Scanner sc = new Scanner(System.in);
        int num;
        System.out.println("Please enter a 3 digit number: ");
        num = sc.nextInt();
        while(num < 100 || num > 999) {
            System.out.println("Bad input! Please enter a 3 digit number: ");
            num = sc.nextInt();
        }
        System.out.println("You entered: " + num);

        //--------------------------Ex3--------------------------------

        Scanner sc = new Scanner(System.in);
        int num;
        System.out.println("Please enter a 2 digit number with same digits: ");
        num = sc.nextInt();
        while((num < 10 && num > 99) || (num/10 != num%10)) {
            System.out.println("Bad input! Please enter a 2 digit number with same digits: ");
            num = sc.nextInt();
        }
        System.out.println("You entered: " + num);

        //---------------------------Ex4---------------------------

        Scanner sc = new Scanner(System.in);
        int num;
        System.out.println("Please enter a 3 digit number that is a 7 multiplication: ");
        num = sc.nextInt();
        while((num < 100 && num > 999) || (num%7 != 0)) {
            System.out.println("Bad input! Please enter a 3 digit number that is a 7 multiplication: ");
            num = sc.nextInt();
        }
        System.out.println("You entered: " + num);

        //---------------------------Ex4---------------------------

        Scanner sc = new Scanner(System.in);
        int num;
        System.out.println("Please enter a number: ");
        num = sc.nextInt();
        int n = num % 10;
        boolean b = true;
        while(num/10 != 0 && b) {
            num /= 10;
            if(n != num%10) {
                b = false;
            }
        }
        if(b) {
            System.out.println("All digits are the same");
        } else {
            System.out.println("Not all digits are the same");
        }
    }
}