Thread: Java ... I Need Your Help so I Can Help My Son

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

public class TheBrainGame2
{
static String Rating;
static int count;
static int Random;
static int Guess;


public static void main(String[] args)
{
Guess = count;
if (count <= 10)
{
Rating = Rating(count);
}
}


public static int NumberGenerator(int Random)
{
Random RandomNumber = new Random(12);
count = 0;
for(int x = 0; x < 100; x++)

{
int Number = 1 + RandomNumber.nextInt(100);
System.out.print(Number + " ");
count++;
if(count > 15)

{
System.out.println(" ");
count = 0;
}
}

return Random;
}


public static String Rating(int count)
{
{
if(count > 10)
Rating = "Fail! You are a Cyber Dud!";
if(count == 10)
Rating = "Circuit Breaker";
if(count <= 9)
Rating = "Techno Geek";
if(count <= 7)
Rating = "Super Chip";
if(count <= 5)
Rating = "Cyber Brain";
if(count <= 3)
Rating = "Micro Genius";
if(count == 1)
Rating = "Genius";
}
return Rating;
}



public static void Answer(int Answer)
{
Scanner input = new Scanner(System.in);
int x;
System.out.println("Enter your answer please");
x = in.nextInt();
}


public static String Guess(int Guess)
{
while(Guess != Random && count >= 10)
System.out.println("Enter Guess #");
if(Guess < Random)
System.out.println("Wrong! you are too low!");
if(Guess > Random)
System.out.println("Wrong! you are too high!");
if(Guess == Random)
System.out.println("Correct! you are a ...");
count = count + 1;
return Rating;
}
}

fails to compile.

Please copy and paste here the full text of the error messages.
We don't write code for you, you will have to write the code. When you have problems or questions, post them.

Also posted at: http://www.java-forums.org/new-java/...lp-my-son.html

Don't be discouraged about your son's progress. It is possible that his brain doesn't work the way a programmer's brain works. Not everyone can easily learn programming. I see a couple of students a month that never get it.
I read a good blog about this several months ago, but don't have a link to it.

Every java file you submit to the compiler must be syntactically correct to get a clean compile.
I don't know about the technique of commenting out sections of a program that does not compile. I'd rather start with a skeleton of the class and its methods and incrementally add code in small chunks and compile often. Fix the errors and compile again until no errors, then add a few more lines and do it again.
Having a lot of unused code in the source could be confusing.

Back on topic,

I agree with norm and curmudgeon about the top-down approach rather than the left-to-right approach.

Frame out the basic structure (what classes you need, a rough idea of what methods and fields, etc.) and make sure this structure compiles and runs, even if it doesn't do anything. Bonus points are to go back after you have the basic structure done and add comments to describe what it is you want to do in a method and roughly the order you want to do it in.

ex. (a little more verbose than you would usually want to do, but it illustrates the purpose)

public class SomeClass
{
    /**
    * Prints the name and age of a person
    */
    public static void printInfo(String name, int age)
    {
        // print out the name
        // print out the age
    }
 
    /**
    * Converts a person's age in years to months, days, hours, minutes, and seconds
    */
    public static int[] ageConverter(int age)
    {
        // initialize the results array
        int[] results = new int[5];
        // calculate age in months
        // calculate age in days
        // calculate age in hours
        // calculate age in minutes
        // calculate age in seconds
 
        return results;
    }
 
    public static void main(String[] args)
    {
        // ask the user for their name
        // ask the user for their age
        // print out the basic info
        // convert their age to other time units and print it out
    }
}

At this point you can switch to the left-to-right approach for implementing the methods as these tend to be somewhat linear. Build and test your code often! This helps you to make sure what you're coding didn't break something else and does what you want it to.

Last remarks (slightly off-topic again):

Regardless of how you write/compile your code I would suggest you format your code using spaces/tabs. The general rule of thumb is after every open curly brace you indent by 1 tab and after every closing curly brace you de-dent by 1 tab. If you do this properly you can identify errors where you have a missing brace and/or extra braces much easier. it also makes reading your code much simpler as you can tell what blocks of code are related to each other.

You can get near-bare-bones editors which have nothing more than a text editor with syntax highlighting and auto-indentation. This gives you the two most useful benefits for beginners that IDE's offer without any potential pitfall or short-coming. If you use Windows, I would recommend using Notepad++. For Linux GEdit has these features, and I think Emacs/XEmacs do too (not positive about this, though). I'm not sure what to use with Macs since I've never really used one.

The [] denotes an array. More information about arrays: Arrays (The Java™ Tutorials > Learning the Java Language > Language Basics)

Originally Posted by Norm

Please copy and paste here the full text of the error messages.
We don't write code for you, you will have to write the code. When you have problems or questions, post them.

Also posted at: Java ... I Need Your Help so I Can Help My Son

I edit the code and removed the comments.

The error that the compiler is highlighted is:

public static void Answer(int Answer)
{
Scanner input = new Scanner(System.in);
int x;
System.out.println("Enter your answer please");
x = in.nextInt();

}

The error that the compiler is highlighted

Please copy and paste here the full text of the error messages. Sorry, I can't see your computer or its highlighting.
Here is a sample of an error message from the javac compiler:

TestSorts.java:138: cannot find symbol
symbol  : variable var
location: class TestSorts
         var = 2;
         ^

My son and classmate figured out the error. But can some explain why?

public static void Answer(int Answer)
{
Scanner input = new Scanner(System.in);
int x;
System.out.println("Enter your answer please");
x = input.nextInt();
 
 
 
}

Originally Posted by Norm

Please copy and paste here the full text of the error messages. Sorry, I can't see your computer or its highlighting.
Here is a sample of an error message from the javac compiler:

TestSorts.java:138: cannot find symbol
symbol  : variable var
location: class TestSorts
         var = 2;
         ^

I highlighted the error in red.


x = in.nextInt();


"cannot find symbol - variable in"

x =in.nextInt();

cannot find symbol - variable in

The compiler could not find a definition for the variable: in
Where was in defined? You must define all variables before using them.

After numerous hours and attempts at trying to understand Java on this particular coding of "Guessing The Number", I was able to find a code similar to my initial question.

Unfortunately, and as a first time user of Java, it is not easy. Not even with ALL the tutorials on the web. The "Hello World" example doesn't do any justice, at least to me. The "Guess The Number" program on the web gives a somewhat decent explanation to an already sought out question.

But there are a lot of Java information on the web that lacks explanation by example, in my opinion to get me on track. So here's what I learned during the initial learning curve process based on the question "Design a program based on the following:"


1) User input guesses a number.
2) Computer generates a random number and stores it in memory.
3) User has ? tries.
4) Program responds by printing on the screen if the user guess is low, high, correct, or failed.

Now this may seem simple to the already seasoned Java Programer, but to me, I haven't a clue. The first approach is to break the question in a logical manner .....

1) Write a program to generate a random number.

Well you have to first start by understanding what this part of the code does. This is simple and I understand the function of the below code.

public class NumberGuessing {
 
      public static void main(String[] args) {
 
       }
 
}

The part I don't understand are the library of names that are not listed. I can easily find the Java "Key Words", "Operators", "Element", etc on a Java Syntax cheat sheet. The library names like "random", "println", "import java.util.*", "math", etc. How do I learn these without doing several simple practice java coding by examples?

Can anyone lead me in the right direction on taking a java coding approach based on the question? I provided a WORKING java program just so "YOU" won't have to give me the written java code answer. There is an explanation on the below java code but it doesn't explain things like using Math.random or where to find Math and random.

 
 
import java.util.Scanner;
 
 
 
public class NumberGuessingGame {
 
      public static void main(String[] args) {
 
            int secretNumber;
 
            secretNumber = (int) (Math.random() * 999 + 1);
 
            System.out.println("Secret number is " + secretNumber); // to be removed
 
            // later
 
            Scanner keyboard = new Scanner(System.in);
 
            int guess;
 
            do {
 
                  System.out.print("Enter a guess: ");
 
                  guess = keyboard.nextInt();
 
                  System.out.println("Your guess is " + guess);
 
                  if (guess == secretNumber)
 
                        System.out.println("Your guess is correct. Congratulations!");
 
                  else if (guess < secretNumber)
 
                        System.out
 
                                   .println("Your guess is smaller than the secret number.");
 
                  else if (guess > secretNumber)
 
                        System.out
 
                                   .println("Your guess is greater than the secret number.");
 
            } while (guess != secretNumber);
 
      }
 
}

How do I learn these without doing several simple practice java coding by examples?

I think writing several simple java programs is a good way to learn. I don't know a shorter way.