Question

Two people play the game of Count 21 by taking turns entering a 1, 2, or 3, which
is added to a running total. The player who adds the value that makes the total
reach or exceed 21 loses the game. Create a game of Count 21 in which a player
competes against the computer, and program a strategy that always allows the
computer to win. On any turn, if the player enters a value other than 1, 2, or 3,
force the player to reenter the value. Save the game as
Count21.java

Answer 1

Count21.java

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

public class Count21 {
   public static void main(String[] args) {
       // Scanner class object to accept input from user
       Scanner input=new Scanner(System.in);
       // Random class object to generate random number
       Random random=new Random();
       System.out.println("*** COUNT 21 GAME ***");
       int yourTotal=0;
       int computerTotal=0;
       while(true) {
           int value;
           while(true) {
               System.out.print("Enter a value (1/2/3): ");
               value=input.nextInt(); // accept value from user
               // check entered value is correct or not
               if(value==1 || value==2 || value==3)
                   break;
               System.out.println("You entered wrong value..try again.!");
           }
           // add value into user's total
           yourTotal+=value;
           // generate random number betweeen 1 to 3
           // and add it into computer's total
           computerTotal+=random.nextInt((3-1)+1)+1;
           // check user's total
           if(yourTotal>=21) {
               System.out.println("\n*** Computer won the game ***");
               break;
           }
           // check computer's total
           if(computerTotal>=21) {
               System.out.println("\n*** Congratulations...!!! You won the game ***");
               break;
           }
       }
       System.out.println("*** THANK YOU ***");
       input.close(); // close Scanner object
   }
}

Output