How would i create a game?

[Daniel Hoang]

So i have a main class, which is this. Im supposed to create 6 classes based on the 6 games and im wondering if i can input "1" for case 1, then have it run a class based on game 1. Is this possible?

import java.util.Scanner;
public class Project4 {
public static void main(String[] args) {
	
int choice;

	System.out.println("This program allows you to play several games using a random number generator.");	
do
{
	System.out.println();
	System.out.println("Here are the available games to play.");
	System.out.println();
	System.out.println("1. Throw a particular die number a certain number of times in a row.");
	System.out.println("2. Build a chart displaying the randomness of the 6 die numbers.");
	System.out.println("3. Throw a given pattern of six dice.");
	System.out.println("4. Find the percent difference for each die number from the average, given a certain number of throws.");
	System.out.println("5. Guess the computer generated random number between 1 and 100.");
	System.out.println("6. Guess a five digit number.");
	System.out.println("7. Quit playing.");
	System.out.println();
	System.out.println("Please enter in the number for one of the 7 choices");
	Scanner keyboard = new Scanner(System.in);
	choice = keyboard.nextInt();
	
	switch (choice)
	{
	case 1:
		System.out.println("Game 1.");
		break;
	case 2:
	System.out.println("Game 2");
		break;
	case 3:
		System.out.println("Game 3");
		break;
	case 4:
		System.out.println("Game 4");
		break;
	case 5:
		System.out.println("Game 5");
		break;
	case 6:
		System.out.println("Game 6");
		break;
	case 7:
		System.out.println("Exitting");
		break;
	}
} while (choice < 7);
}
}

[Jeff Verdegan]

So, you're asking if Java has a facility whereby you can choose a particular course of action depending on user input? It would be a pretty useless programming language if it didn't. And you already know the answer anyway, since the code you posted is already doing just that.

[Daniel Hoang]

I dont know how to better word my question. Like if i have object classes, Game 1, 2 ,3 4, 5, and 6, all with different games. How can i have the user input "1" and the Game 1 class will execute?

[Jeff Verdegan]

Daniel Hoang wrote:I dont know how to better word my question. Like if i have object classes, Game 1, 2 ,3 4, 5, and 6, all with different games. How can i have the user input "1" and the Game 1 class will execute?

Your question is actually just "How can I get the Game 1 class to execute?"

You already know how to do the part, "If the user inputs 1, how do I do something corresponding to 1?" I can see that you know the answer to that question, because you're doing it here:

    case 1:  
        System.out.println("Game 1.");  
        break;  

If you wrote that code, and you understand what it does, then you know the answer to the first part of your question. So that only leaves the second part: "How do I execute Game 1?"

That answer also has to come from you, at least in part. You haven't told us anything about what it means to "execute the class for Game 1", so we don't know what you're actually trying to do. One example might be:

Game1 game1 = new Game1();
game1.execute();

That's not the only possibility of course, just the simplest one that corresponds most directly to what little information you've provided.

[Daniel Hoang]

Yes i think thats the answer i was looking for. Sorry i couldnt be clearer about how i wanted to execute the class for game 1 because i am currently working on the class now. This is what i have so far as a frame of reference. Thanks for your answer.

import java.util.Scanner;
public class Game1 {
public static void main(String[] args) {
	Scanner keyboard = new Scanner(System.in);
	int face, times;
	System.out.println("This game throws a die until a certain die face number appeaers a certain number of times in a row");	
	
	do
	{
	System.out.println("Enter the die face number from 1 - 6 that you'd like to be repeated");
	face = keyboard.nextInt();
	} while ((face < 0) || (face > 7));
	
	do
	{
	System.out.println("Now enter the number of times that you'd like the number " + face + " to appear in a row");
	times = keyboard.nextInt();
	} while((times < 0));
	System.out.println("This program will now see how many throws it takes to have the number " + face + " to appear " + times + " times");
	

	
	}

}

[Daniel Hoang]

Ok so i got the class to execute, but now im having a logic error with my dice game. Im not sure how exactly to repeat the rolls until i get the entered number to repeat the entered amount of times. When i try the way i do here below, nothing comes out. What could i be missing in my logic?

import java.util.Scanner;
public class Game1 {
public static void main(String[] args) {
	
	Scanner keyboard = new Scanner(System.in);

	int face, times, roll, numberOfRolls = 1, landsOnFace = 0;
	System.out.println("This game throws a die until a certain die face number appeaers a certain number of times in a row");	
	
	do
	{
	System.out.println("Enter the die face number from 1 - 6 that you'd like to be repeated");
	face = keyboard.nextInt();
	} while ((face < 0) || (face > 7));
	
	do
	{
	System.out.println("Now enter the number of times that you'd like the number " + face + " to appear in a row");
	times = keyboard.nextInt();
	} while((times < 0));
	
	System.out.println("This program will now see how many throws it takes to have the number '" + face + "' appear " + times + " times");
	// this is where im having trouble V
	do
	{
		roll = (int) (1 + Math.random()* 6);
		if ((roll == face) && (times == landsOnFace)){
			numberOfRolls = numberOfRolls++;
			System.out.println(numberOfRolls);
		}
			else if ((roll == face) && (times != landsOnFace))
			numberOfRolls = numberOfRolls++;
			landsOnFace = landsOnFace++;

} while (!((roll == face) && (times == landsOnFace)));
	
	System.out.println(numberOfRolls);

}
}

[Jeff Verdegan]

Your code is rather hard to follow, so I didn't study it in detail. This is always wrong though:

x = x++;

That is equivalent to:

tmp = x;
x = x + 1;
x = tmp;

which boils down to:

x = x;

which does exactly nothing.

If you want to increment x, simply do:

x++;

If you set some variable to hold the value of x before it gets incremented, you can do:

y = x++;

in which case if x goes from 5 to 6, y will get the value 5. (So, as I said above, if you have x on the LHS instead of y, then x just gets reassigned whatever value it already has.)

[Daniel Hoang]

Oh i see, that makes sense. It still doesnt make my code loop correctly, so something else must be wrong. What also makes my code hard to read out of curiosity?

[Jeff Verdegan]

Daniel Hoang wrote:What also makes my code hard to read out of curiosity?

Not sure. Might be the indentation's a little weird. Might be because I'm tired.

Also, don't do this:

 int face, times, roll, numberOfRolls = 1, landsOnFace = 0;  

Declare one variable per line:

int face;
int times;
int roll;
int numberOfRolls = 1;
int landsOnFace = 0;  

[Daniel Hoang]

Ah ok. I do both, but sometimes i end up putting all of them on one line because im too lazy to scroll further up and down haha

[vikram setty]

Hi ,


I agree with Jeff for the solution to the problem. Nevertheless, a good maintainable code use the power of polymophism and design patterns.

You should have an interface called Game and six specific implementation classes Game1, Game2... Game6 implement this interface .

In you subsequent main code use only the Game gm = getGame();

getGame() method should create a specific Game object based on the user input for eg: new Game1 () should be returned if user selects 1 .

Regards
Vikram

[Daniel Hoang]

I have not learned interfaces or polymorphisms yet. but i am close to getting my loops to work at least.

[Campbell Ritchie]

There is something wrong with putting descriptions of the games in the main method. The main method should simply start off the application, so I think its ideal length is one statement. You can call other methods which give you the choice of games. But those methods should not have the descriptions of the games either. The descriptions are part of the game, and should therefore live in the game classes.

[Campbell Ritchie]

Daniel Hoang wrote:I have not learned interfaces or polymorphisms yet. but i am close to getting my loops to work at least.

That makes it sound as though you are trying to do several things simultaneously. Don’t. Do one thing, get it working and then move on to the next thing.

[Daniel Hoang]

Im not trying to do several things at once. Im still currently working on making my loops work, it just takes me a while.

[Winston Gutkowski]

Daniel Hoang wrote:Im not trying to do several things at once.

Actually, you are; otherwise Campbell wouldn't have said it. For starters, you have 7 games that you're trying to implement.
Why not one? Design it, code it, test it; and then move on to the next.

Im still currently working on making my loops work, it just takes me a while.

Well, most of your problems (as has already been said) stem from the fact that all your logic is crammed into a single method (main()), which is almost always a bad way to go.

My advice: StopCoding (←click). Work out what you're trying to do on paper and in English (or your native language).
You will never code your way out of a mess.

Winston

PS: Please DontWriteLongLines (←click). It makes your post very hard to read. I'd break them up myself, but there are tons of them.
You can do it yourself with the 'Edit' button. Remember: 80 characters maximum.

[Daniel Hoang]

Oh my mistake. Im not having trouble on my main method!! Ive been working on game 1 after i figured out the solution to my main. Thats why ive been saying that im working on one thing at a time. By loops, i meant the dice loops in my game1 class. Also, thanks for the tips, ill keep them in mind.

[Campbell Ritchie]

Daniel Hoang wrote: . . . By loops, i meant the dice loops in my game1 class. . . .

And I though you meant those three do loops in the main method. You need to be clear; remember we can’t look over your shoulder and see what you are doing. (I bet you are pleased about that ‍).
And think of a better name for that class than game1.

[Daniel Hoang]

thanks for your help. i thought i mentioned that i finished the main method and moved on to the class but Im have a huge tendency to be unclear. i was wondering why everyone was telling me i was doing more than one thing.

[Campbell Ritchie]

Don’t code from the main method outwards. Code from the periphery, which means your basic classes, towards the centre.

[Paul Clapham]

You asked about what makes your code hard to read. Here's an example:

        if ((roll == face) && (times == landsOnFace)){  
            numberOfRolls = numberOfRolls++;  
            System.out.println(numberOfRolls);  
        }  
            else if ((roll == face) && (times != landsOnFace))  
            numberOfRolls = numberOfRolls++;  
            landsOnFace = landsOnFace++;  

Sure, you are using indentation, but the indentation doesn't match the actual code logic. The "else if" statement controls only the next statement, whereas the indentation implies it controls the next two statements. This can be very misleading and prevent you from finding bugs. Indentation which matches the actual code logic would be like this:

        if ((roll == face) && (times == landsOnFace)){  
            numberOfRolls = numberOfRolls++;  
            System.out.println(numberOfRolls);  
        }  
        else if ((roll == face) && (times != landsOnFace))  
            numberOfRolls = numberOfRolls++;  
        landsOnFace = landsOnFace++;  

[Jeff Verdegan]

Paul Clapham wrote:Indentation which matches the actual code logic would be like this:

        if ((roll == face) && (times == landsOnFace)){  
            numberOfRolls = numberOfRolls++;  
            System.out.println(numberOfRolls);  
        }  
        else if ((roll == face) && (times != landsOnFace))  
            numberOfRolls = numberOfRolls++;  
        landsOnFace = landsOnFace++;  

And better still would be to use braces, so that it's clear what you intended to be part of the else and what you intended not. (And still using proper indentation of course.)

Always use braces for if, else, for, while, even when they're not strictly necessary.

        else if ((roll == face) && (times != landsOnFace))  {    // <---- ADD THIS BRACE
            numberOfRolls = numberOfRolls++;  
        } //                                 <---- AND THIS ONE
        landsOnFace = landsOnFace++;  

And of course, proper use of ++ :

        else if ((roll == face) && (times != landsOnFace))  {   
            numberOfRolls++;  
        } 
        landsOnFace++;  

[Daniel Hoang]

Oh ok, here is my code, i think it looks pretty good i hope.

import java.util.Scanner;
public class Game1 {
public static void main(String[] args) {
	
}	
   private int nextRoll;
   private int faceNumber;
   private int appearsInARow;
   private String answer = "yes";
	
    public void execute() {
    	Scanner keyboard = new Scanner(System.in);
      
do {
    System.out.println("This game throws a die until a certain die face number appears a certain number of times in a row");

	do {
		System.out.println("Enter the die face number from 1 - 6 that you'd like to be repeated");
		faceNumber = keyboard.nextInt();
		} while ((faceNumber <= 0) || (faceNumber >= 7));
	
	do {
		System.out.println("Now enter the number of times that you'd like the number " + faceNumber + " to appear in a row");
		appearsInARow = keyboard.nextInt();
		} while((appearsInARow < 0));
	
	int tries = 0;
	int timesLandedOnFaceInARow = 0;
	
	do {
	      nextRoll = (int) (1 + Math.random()* 6);
	 
	     if ((nextRoll == faceNumber) && (timesLandedOnFaceInARow != appearsInARow)) {
	    	  tries++;
	    	  timesLandedOnFaceInARow++;
	     }
	      
	     if ((timesLandedOnFaceInARow == appearsInARow) && (nextRoll == faceNumber)) {
	      	  System.out.println("After " + tries + ", tries, the number " + faceNumber + " has appeared " + appearsInARow + " times in a row");
	     }	  
	      
	     if (nextRoll != faceNumber) {
			  tries++;
			  timesLandedOnFaceInARow = 0;   
 	  	 }
	    	   
	     } while (appearsInARow != timesLandedOnFaceInARow);
System.out.println();
System.out.println("Would you like to play again? Yes or no");	
answer = keyboard.next();
 	
} while (answer.equalsIgnoreCase("yes"));
}
}
 

[Jeff Verdegan]

Somewhat better, but the indentation is still pretty icky.

I notice that you have a mixture of spaces and tabs for the indentation, so that's at least part of the problem. You should always use only spaces (never tabs) for indenting. You should be able to set your editor up to indent up to a multiple of N spaces when you hit the tab key, where N is configurable by you, but should be 4 (or better yet, 2, IMHO, but 4 is more standard).

[Daniel Hoang]

Ah ok. It always annoyed me that the tab button wouldnt be consistent everytime i pressed it.