用户无法下注的值仍然可以使用

Question

For my CS assignment, I set up a range of values in my code where the user can only bet coins from 1-10. However even though I set this range of values up, whenever I bet a certain amount of coins such as 15 which is not in the range, it thinks it's a good number that it can be bet. This is the piece of code where the range is located:

do {

             System.out.print(" How much would you like to bet? ");
             System.out.println("");
             userBet = input.nextDouble();            
             userCoins = (userCoins - userBet);
             numOfSpins++;

             if (userBet > userCoins || userBet > 10) {
                 System.out.println("The number of coins you can bet can only be from 1-10!");

             }
             else if (userBet >= 1 && userBet <= 10) {

             }

            } while (userBet < 1 || userBet > 10);

And heres the rest of my code for better context:

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

public class SlotMachine {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        Scanner input = new Scanner(System.in);
        Random randInt = new Random();


        System.out.println("Welcome to The Royal Casino!");

        System.out.println("");
        System.out.println("Remember, getting:");
        System.out.println("### means x2"); 
        System.out.println("$$$ means x5");
        System.out.println("&&& means x20");
        System.out.println("@@@ means x100");

        System.out.println("");
        System.out.println("Now, you will be starting off with 100 coins. Good luck!");

        double userCoins = 100.00; //Total number of coins you have
        double userBet = 0; //The user's bet with how much coins he/she has
        double numOfSpins = 0; //The number of spins the user does
        double win = 0;
        double loss = 0;
        String quitKey = "q"; //The key the user enters to quit

        do {

            do {

             System.out.print(" How much would you like to bet? ");
             System.out.println("");
             userBet = input.nextDouble();            
             userCoins = (userCoins - userBet);
             numOfSpins++;

             if (userBet > userCoins || userBet > 10) {
                 System.out.println("The number of coins you can bet can only be from 1-10!");

             }
             else if (userBet >= 1 && userBet <= 10) {

             }

            } while (userBet < 1 || userBet > 10);

            int spin1 = randInt.nextInt(4) + 1;
            int spin2 = randInt.nextInt(4) + 1;
            int spin3 = randInt.nextInt(4) + 1;
            String spinName1 = " ", spinName2 = " ", spinName3 = " ";

            switch (spin1)
            {
                case 1:
                    spinName1 = "#"; break;
                case 2:
                    spinName1 = "$"; break;
                case 3:
                    spinName1 = "&"; break;
                case 4:
                    spinName1 = "@"; break;
            }

            switch (spin2)
            {
                case 1:
                    spinName2 = "#"; break;
                case 2:
                    spinName2 = "$"; break;
                case 3:
                    spinName2 = "&"; break;
                case 4:
                    spinName2 = "@"; break;
            }

            switch (spin3)
            {
                case 1:
                    spinName3 = "#"; break;
                case 2:
                    spinName3 = "$"; break;
                case 3:
                    spinName3 = "&"; break;
                case 4:
                    spinName3 = "@"; break;
            }

            System.out.println("-------------------------------");
            System.out.printf("%-12s%-10s%5s\n", spinName1, spinName2, spinName3);
            System.out.print("-------------------------------\n");

            if (spin1 == 1 && spin2 == 1 && spin3 == 1)
            {
                userCoins = userCoins + (userBet * 2);
                win++;
                System.out.printf("3 in a row! You have won: $%.2f",(userBet * 2));
                System.out.println("You have spun " + numOfSpins);
                System.out.printf(" You currently have: $%.2f", userCoins);
            }
            else if (spin1 == 2 && spin2 == 2 && spin3 == 2)
            {       
                userCoins = userCoins + (userBet * 5);
                win++;
                System.out.printf("3 in a row! You have won: $%.2f",(userBet * 5));
                System.out.println("You have spun " + numOfSpins);
                System.out.printf(" You currently have: $%.2f", userCoins);
            }
            else if (spin1 == 3 && spin2 == 3 && spin3 == 3)
            {
                userCoins = userCoins + (userBet * 20);
                win++;
                System.out.printf("3 in a row! You have won: $%.2f",(userBet * 20));
                System.out.println("You have spun " + numOfSpins);
                System.out.printf(" You currently have: $%.2f", userCoins);
            }
            else if (spin1 == 4 && spin2 == 4 && spin3 == 4)
            {
                userCoins = userCoins + (userBet * 100);
                win++;
                System.out.printf("3 in a row! You have won: $%.2f",(userBet * 100));
                System.out.println("You have spun " + numOfSpins);
                System.out.printf(" You currently have: $%.2f", userCoins);
            }
            else
            {
                loss++;
                System.out.println("You have won nothing. Try again!");
                System.out.println("You have spun " + numOfSpins);
                System.out.printf(" You currently have: $%.2f", userCoins);

            }
        } while (userCoins > 0);
        System.out.println(" Oops! You have no more coins. Maybe next time you'll be more lucky!");
        System.out.println("Your total balance is " + userCoins);
        System.out.println("Your total spins were " + numOfSpins);
        System.out.println("Your total wins are " + win + " and total losses are " + loss);
    }

}

Thank you!

Answer 1

At the start of that do-while loop, you have userCoins = (userCoins - userBet); , which means that even if the input is completely invalid, the bet value will still be removed every time. This line should be after it's exited the first do-while loop. Once that's done, your program works fine as far as I can tell, and rejects invalid bets.