Random number guessing game 456

Question

This code is working well, I am just fairly new to programming and am hoping someone more experienced can look it over and give me some pointers.

 * Author: Tyler Knight
 * Date Created: 02/07/2018
 * Program Purpose: Guessing game using
 * random numbers.
 **/


//Importing random and scanner classes
import java.util.Random;
import java.util.Scanner;

public class ElusiveNumbers {

    public static void main(String[] args) {

        //Declare variables
        Random num = new Random();
        int userInput;
        int answer;
        int count;
        int attempts;
        int restart;
        int terminate;
        int range;
        Scanner keyboard = new Scanner(System.in);

        //Whitespace
        System.out.println();
        System.out.println();

        try {

            //Greeting Message
            System.out.println("Welcome To Elusive Numbers!");

            //Whitespace
            System.out.println();

            //Prompt user to enter number range
            System.out.println("Enter the range of numbers you would like to guess from. EX: 5, 10, 100, 1000");

            //Whitespace
            System.out.println();

            //Allows User To Enter Range
            range = keyboard.nextInt();

            //Whitespace
            System.out.println();

            //Prompt user to enter in however many chances they would like to have
            System.out.println("Enter the amount of attempts you would like for this challenge");

            //Whitespace
            System.out.println();

            //Allows user to set amount of attempts
            attempts = keyboard.nextInt() - 1;

            //Whitespace
            System.out.println();

            //Prompt user to guess the number
            System.out.println("Enter a number between 1 and " + range);

            //Whitespace
            System.out.println();
            System.out.println();

            //Assign value to variables
            answer = num.nextInt(range) + 1;
            count = 0;



            /*
            * While the user input is not equal to the random generated number,
            * it will tell the user if their number was too high or too low,
            * it will also add 1 to the count variable every time user is wrong,
            * if the count variable becomes equal to 3 "Game Over" will display,
            * the user will then have the chance to try again or exit the game
            */


            do {
                //Assign value to variables
                userInput = keyboard.nextInt();
                restart = 1;
                terminate = 0;

                //If the count is higher than the attemps and user has not guessed the number, Game Over
                if (count >= attempts && userInput != answer) {

                    //If user guess is too low, output Too Low!
                    if (userInput < answer) {
                        //Whitespace
                        System.out.println();

                        System.out.println("Too Low!");

                    } 
                    //If user guess is too high, output Too High!
                    else if (userInput > answer) {
                        //Whitespace
                        System.out.println();

                        System.out.println("Too High!");
                    }

                    //Whitespace
                    System.out.println();

                    System.out.println("Game Over!");

                    //Whitespace
                    System.out.println();

                    System.out.println("To try again, type 1, to quit type 0");

                    //Whitespace
                    System.out.println();

                    userInput = keyboard.nextInt();

                    //Whitespace
                    System.out.println();

                    //If the user Chooses to restart the game will reset, Else the program will exit 
                    if (userInput == restart) {
                        count = 0;
                        answer = num.nextInt(range) + 1;

                        System.out.println("Enter the range of numbers you would like to guess from. EX: 5, 10, 100, 1000");

                        //Whitespace
                        System.out.println();

                        range = keyboard.nextInt();

                        //Whitespace
                        System.out.println();

                        System.out.println("Enter the amount of attempts you would like for this challenge");

                        //Whitespace
                        System.out.println();

                        attempts = keyboard.nextInt() - 1;

                        //Whitespace
                        System.out.println();

                        System.out.println("Enter a number between 1 and " + range + "\t");

                        //Whitespace
                        System.out.println();
                    }

                    else if (userInput == terminate) {
                        return;
                    }
                }

                // If the counter is at it's limit but the answer is correct it will not go to game over
                else if (count == 2 && userInput == answer) {
                    System.out.println("Great Job!");

                    System.out.println("To try again type 1, to quit type 0");

                    userInput = keyboard.nextInt();

                    //If user chooses to restart, everything will reset and game will start over
                    if (userInput == restart) {
                        count = 0; // Resets count
                        answer = num.nextInt(range) + 1; // Resets random number

                        System.out.println("Enter the range of numbers you would like to guess from. EX: 5, 10, 100, 1000");

                        //Whitespace
                        System.out.println();

                        range = keyboard.nextInt();

                        //Whitespace
                        System.out.println();

                        System.out.println("Enter the amount of attempts you would like for this challenge");

                        //Whitespace
                        System.out.println();

                        attempts = keyboard.nextInt() - 1;

                        System.out.println("Enter a number between 1 and " + range + "\t");

                        //Whitespace
                        System.out.println();

                    } 
                    else if (userInput == terminate) {
                        return;
                    }
                }

                else if (userInput > answer) {

                    //Whitespace
                    System.out.println();

                    System.out.println("Too high!");

                    //Whitespace
                    System.out.println();

                    count = count + 1;

                }

                else if (userInput < answer) {

                    //Whitespace
                    System.out.println();

                    System.out.println("Too Low!");

                    //Whitespace
                    System.out.println();

                    count = count + 1;
                }

                //If guess is equal to random number, user wins and chooses whether or not to restart.
                else if (userInput == answer) {

                    System.out.println("Great Job!");

                    System.out.println("To try again type 1, to quit type 0");

                    userInput = keyboard.nextInt();

                    if (userInput == restart) {

                        count = 0; //Resets count
                        answer = num.nextInt(range) + 1; //Resets random number

                        System.out.println("Enter the range of numbers you would like to guess from. EX: 5, 10, 100, 1000");

                        //Whitespace
                        System.out.println();

                        range = keyboard.nextInt();

                        //Whitespace
                        System.out.println();

                        System.out.println("Enter the amount of attempts you would like for this challenge");

                        //Whitespace
                        System.out.println();

                        attempts = keyboard.nextInt() - 1;

                        //Whitespace
                        System.out.println();

                        System.out.println("Enter a number between 1 and " + range + "\t");

                        //Whitespace
                        System.out.println();

                    } 
                    else if (userInput == terminate) {
                        return;
                    }
                }
            }
            while (userInput != answer || count < attempts);
        }
        //Exception Handler
        catch (Exception all){
            System.out.println("Please enter a valid integer and try again.");
        }
    }

I don't know much about Java conventions, but I'm pretty sure //Assign value to variables is not a very good comment. (the //Whitespace is pretty useless too) — internet_user, Feb 11, 2018 at 1:33
Thanks dude, what would you suggest as a better comment for the variables then? — RobotMan, Feb 11, 2018 at 1:48
Maybe just nothing, it's not that hard to tell what it does. — internet_user, Feb 11, 2018 at 2:04
(Welcome to CR!) (The code presented misses a line (easy to guess) at the top. In general, be easy on vertical screen space.) — greybeard, Feb 11, 2018 at 5:36
Please do not update the code in your question to incorporate feedback from answers, doing so goes against the Question + Answer style of Code Review. This is not a forum where you should keep the most updated version in your question. Please see what you may and may not do after receiving answers. — Simon Forsberg, Feb 12, 2018 at 19:43

greybeard · Accepted Answer · 2018-02-11 08:21:55Z

Don't Repeat Yourself
With the 3rd occurrence of a sequence like add screen space, prompt user, parse an int, you should abstract that:

/** Prompt for an int. */
static int promptInt(Scanner keyboard, String prompt) {
    System.out.println();
    System.out.println(prompt);
    System.out.println();

    while (!keyboard.hasNextInt()) {
        keyboard.next();
        System.out.println("try again:");
    }
    return keyboard.nextInt();
}

use try-with-resources:

try (Scanner keyboard = new Scanner(System.in)) {
    System.out.println("Welcome To Elusive Numbers!");
    range = promptInt(keyboard, "Enter the range of numbers "
        + "you would like to guess from. EX: 5, 10, 100, 1000");

    attempts = promptInt(keyboard, "Enter the amount of attempts "
        + "you would like for this challenge") - 1;

    answer = promptInt(keyboard, "Enter number to be guessed "
        + "between 1 and " + range) + 1;

Don't Repeat Yourself
the code repeats after If the user Chooses to restart

I got tired of scrolling through all those lines after that - just one more thing:
in the very end, you

catch all Exceptions: dangerous
tell the user "Please enter a valid integer and try again.", but terminate execution -
such behaviour may raise scorns

Thanks for taking the time to look at this and give some great advice! — RobotMan, Feb 11, 2018 at 16:42
I like the repeating of 'Don't Repeat Yourself', well played :) — Rob Audenaerde, Feb 13, 2018 at 7:55

Jamal · Accepted Answer · 2018-02-11 21:39:54Z

1

You are in a good place. Some advice to make your code better:

Start using an IDE

The best one for Java developers, in my opinion, is IDEA IntelliJ. There is a community version, at the beginning of you coding adventure it'll be enough. I copied your code to my IDE and before I started reading it I get a message of potential duplicate code. It helps with extracting new methods and new classes, all that stuff. A proper IDE will do a lot of boring stuff for you.
Do not use comments

Your code should be self-explanatory, especially at that small part of code. You can avoid commenting creating a proper class and methods structure.

In your code, I created a new method:
```
private static void addWhitespace() {
    System.out.println();
}
```
Small change but thanks to that I replaced all 33 of System.out.println(), some which was with the comment //Whitespace. We save some space and code is more readable.
Do not write complicated and long methods

Your program has over 200 lines of code and there are no methods. It is hard to read. You can divide it into some parts, such as lines about starting messages to a user. You can extract it to separate method. Also, if you write some nested logic like for inside for inside if etc., divide it to different methods.

Ok, for the moment it should be enough. Please show next version of your code :)

edited Feb 11, 2018 at 21:39

Jamal

34.8k13 gold badges132 silver badges237 bronze badges

answered Feb 11, 2018 at 19:30

Rafalsky

987 bronze badges

\$\begingroup\$ Thank you for the great advice. I see what your saying about putting my repetitive code into methods so I don't take up as much space. In my Computer Science class my instructor is really passionate about documentation in the code so that people that do not code can understand it. I do have to admit I have gone overboard with the comments though. Ill post an updated version here as soon as I get the chance. \$\endgroup\$
– RobotMan
Feb 12, 2018 at 17:49
1

\$\begingroup\$ I disagree with 2. The code will show HOW something works, but not WHY it is chosen to be implemented this way. Comments are meant for people reading the code and understanding why it is coded up in this fashion. For example, a comment could be 'I choose to use an ArrayList because of the o(1) get-performance'. I agree with leaving out comments that describe how the code works if that is trivial. \$\endgroup\$
– Rob Audenaerde
Feb 13, 2018 at 7:55
\$\begingroup\$ Right, I get what your saying. That's what i'm finding difficult in college, they are teaching us how to use logic to solve problems but not really how to write good code. My first example of this code worked, but there was a completely better way to write it. \$\endgroup\$
– RobotMan
Feb 13, 2018 at 15:59

Add a comment |

Martin Frank · Accepted Answer · 2018-02-13 07:49:26Z

what i would really recommend would be to split your code into sepreate code blocks... that increases the readability and reduces complexity...

do {
    ...
    if (count >= attempts && userInput != answer) {

        //If user guess is too low, output Too Low!
        if (userInput < answer) {
            printTooLow();
        } 
        //If user guess is too high, output Too High!
        else if (userInput > answer) {
            printTooHigh();
        }
        printGameOver();
        userInput = keyboard.nextInt();

        //If the user Chooses to restart the game will reset, Else the program will exit 
        if (userInput == restart) {
            reStart();            
        }
        ...
    }
    ...
}while (userInput != answer || count < attempts);

that allows you to re-use code. you can use printTooHigh() later again...

and that really seperates the code into relevant blocks (in your case: methods)

NOTE: the code above is just an example how you could adjust your code.

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