使用不带构造函数参数的对象java

Question

So basically I'm creating a betting program where Player1, Player2, Player3 etc. are objects and each have five initialized fields of -1, which means there is no bet, yet.

I'm asking the users to input their bet number, (these numbers are integers inside of an array) and they can have up to a maximum of five bets, explaining the five initialized fields of -1.

The problem here is I can't seem to find a way to have certain players only input 1 or 2 bets, while another inputs 4 and another 5 for example. My program forces each user to enter 5 integers EVEN if they refuse to bet 5 times. Any way I can make this work?

So here's my driver class: (the other parts of it are irrelevant)

System.out.println("Wheel : 0-32-15-19-4-21-2-25-17-34-6-27-13-36-11-30-8-23-10-5-24-16-33-1-20-14-31-9-22-18-29-7-28-12-35-3-26"); 
        System.out.println("Dealer…Place your bets");

        // initializing the six players of the game

        Player player1 = new Player(-1,-1,-1,-1,-1);
        System.out.println("Player 1: ");
            int number1 = keyin.nextInt();
            int number2 = keyin.nextInt();
            int number3 = keyin.nextInt();
            int number4 = keyin.nextInt();
            int number5 = keyin.nextInt();
                System.out.println("");

        Player player2 = new Player(-1, -1, -1, -1, -1);
        System.out.println("Player 2: ");
            number1 = keyin.nextInt();
            number2 = keyin.nextInt();
            number3 = keyin.nextInt();
            number4 = keyin.nextInt();
            number5 = keyin.nextInt();
                System.out.println("");

        Player player3 = new Player(-1, -1, -1, -1, -1);
        System.out.println("Player 3: ");
            number1 = keyin.nextInt();
            number2 = keyin.nextInt();
            number3 = keyin.nextInt();
            number4 = keyin.nextInt();
            number5 = keyin.nextInt();
                System.out.println("");

        Player player4 = new Player(-1, -1, -1, -1, -1);
            System.out.println("Player 4: ");
            number1 = keyin.nextInt();
            number2 = keyin.nextInt();
            number3 = keyin.nextInt();
            number4 = keyin.nextInt();
            number5 = keyin.nextInt();
                System.out.println("");

        Player player5 = new Player(-1, -1, -1, -1, -1);
            System.out.println("Player 5: ");
            number1 = keyin.nextInt();
            number2 = keyin.nextInt();
            number3 = keyin.nextInt();
            number4 = keyin.nextInt();
            number5 = keyin.nextInt();
                System.out.println("");

        Player player6 = new Player(-1, -1, -1, -1, -1);
            System.out.println("Player 6: ");
            number1 = keyin.nextInt();
            number2 = keyin.nextInt();
            number3 = keyin.nextInt();
            number4 = keyin.nextInt();
            number5 = keyin.nextInt();
                System.out.println("");

And here is my other class for players:

public class Player {

int number1;
int number2;
int number3;
int number4;
int number5;
// constructor for each player at the table
public Player(int number1, int number2, int number3, int number4, int number5) {

    this.number1 = number1;
    this.number2 = number2;
    this.number3 = number3;
    this.number4 = number4;
    this.number5 = number5;

The number1, number2 ... represent the five bets.

Also to clarify, the user can't be asked to input a certain String, int, char whatsoever to let the program know he/she's done inputting their bets. It has to look like this

Player 1: 12 13 15
Player 2: 0 5 4

Answer 1

Follow up of your comment Patrick. This is how you'd use Integer.parseInt

...    
Player player2 = new Player(-1, -1, -1, -1, -1);
System.out.println("Player 2: ");
 try {
                number1 = Integer.parseInt(keyin.nextLine());
                number2 = Integer.parseInt(keyin.nextLine());
                number3 = Integer.parseInt(keyin.nextLine());
                number4 = Integer.parseInt(keyin.nextLine());
                number5 = Integer.parseInt(keyin.nextLine());
                System.out.println("");
    }
    //Code will go to this block when user entered something other than integers
    catch(NumberFormatException e) {
        System.out.println("Done accepting bets from player2");
    }
    ...

Alternatively, could store the output of keyin.nextLine() into a string and apply parseInt or evaluate it for some "keyword" you wanted like so.

String keyedinString = keyin.nextLine();
if(keyinString.equalsIgnoreCase("done betting") {
    throw new Exception();
}

You'll soon realize how repetitive this who process is. Therefore, as others have told suggested consider using arrays and for-loops for your task. Like so.

int[] player1Bets = new int[5];
for(int i=0;i<5;i++) {
   try {
      player1Bets[i] = Integer.parseInt(keyin.nextLine());
   }
   catch(NumberFormatException e) {
       System.out.println("Player1 took" + i + "bets. he is done betting");
   }
}
...

So that, instead of number1, number2, number3, number4 ... etc you'll have the first bet in player1Bets[0], second bet in player1Bets[1] ... Much easier to type out, and code.

Hope things are clear.

Answer 2

There are many ways you can do that:

• Use 1,2,3,4,5 parameters constructors instead if just one with 5 parameter.
• The better way is to make use of BUilder pattern because later you might need to place more than 5 bets so instead of keep on adding constructors this is a better option.
• You can also make use of variable arguments. See When do you use varargs in Java?
• Like @immibs said you can also have like a member variable list which you can then add to as many as you want

Answer 3

You can always loop your input and designate a certain number for the loop to terminate. For example; the bets are 1, 2 and 3 and to stop it from there, the user can input 0 then exit the loop or the program can ask the user everytime whether they wanted to place another bet or not. For example,

Place Bet: 1

Do you want to place another bet? Press 1 for yes and 0 for no

If this question is more on the logic part, then this may help you. I do hope I am of help, I am new here and I tried to answer questions to improve my skills and experience. :)

Answer 4

You may need " Builder Pattern " if you want to pass multiple parameters and the count of parameters is not fixed. Please see https://jlordiales.wordpress.com/2012/12/13/the-builder-pattern-in-practice/ for more info about "Builder Pattern".

Here is an example:

If you have a User class with multiple parameters,

public class User {
  private final String firstName; // required
  private final String lastName; // required
  private final int age; // optional
  private final String phone; // optional
  private final String address; // optional

  public static class UserBuilder {
    private final String firstName;
    private final String lastName;
    private int age;
    private String phone;
    private String address;
    public UserBuilder(String firstName, String lastName) {
      this.firstName = firstName;
      this.lastName = lastName;
    }
    public UserBuilder withAge(int age) {
      this.age = age;
      return this;
    }
    public UserBuilder withPhone(String phone) {
      this.phone = phone;
      return this;
    }
    public UserBuilder withAddress(String address) {
      this.address = address;
      return this;
    }
    public User build() {
      // if(age < 0) { ... } return new User(this);
      // not thread-safe, a second thread may modify the value of age
      User user = new User(this);
      if (user.getAge() < 0) {
        throw new IllegalStateException("Age out of range!"); // thread-safe
      }
      return user;
    }
  }

  private User(UserBuilder builder) {
    this.firstName = builder.firstName;
    this.lastName = builder.lastName;
    this.age = builder.age;
    this.phone = builder.phone;
    this.address = builder.address;
  }

  public String getFirstName() {
    return firstName;
  }
  public String getLastName() {
    return lastName;
  }
  public int getAge() {
    return age;
  }
  public String getPhone() {
    return phone;
  }
  public String getAddress() {
    return address;
  }
}

Use following way to create a new User instance:

User user1 = new User.UserBuilder("Jhon", "Doe")
                    .withAge(30)
                    .withPhone("1234567")
                    .withAddress("Fake address 1234")
                    // maybe more parameters
                    .build();
User user2 = new User.UserBuilder("Tom", "Jerry")
                    .withAge(28)
                    // maybe more parameters
                    .build();