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Thread: I need ur help :|

  1. #1
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    Default I need ur help :|

    hi all ..

    plzzzz...I am novice in Java and I have some queries about some programs that my teacher give them to us.. so I need ur help ..

    Program 1:

    // prints the following:
        //
        // Missy: Meowww!
        // Garfield: Meowww!
        // Lassie: Arf! Arf!
    //
     
     
    interface Animal
    {
        String getName();
        String talk();
    }
     
    abstract class AnimalBase implements Animal
    {
    private final String name;
     
    protected AnimalBase(String name)
        {
            this.name = name;
        }
     
    public String getName()
        {
    return name;
        }
    }
     
    class Cat extends AnimalBase
    {
    public Cat(String name)
        {
    super(name);
        }
     
    public String talk()
        {
    return "Meowww!";
        }
    }
     
    class Dog extends AnimalBase
    {
    public Dog(String name)
        {
    super(name);
        }
     
    public String talk()
        {
    return "Arf! Arf!";
        }
    }
     
    public class TestAnimals
    {
     
    public static void main(String[] args)
        {
    Animal[] animals = 
            {
    new Cat("Missy"),
    new Cat("Mr. Mistoffelees"),
    new Dog("Lassie")
            };
     
    for (Animal a : animals)
            {
    System.out.println(a.getName() + ": " + a.talk());
            }
        }
    }



    private final String name;
    here..why she use " final "?

    protected AnimalBase(String name)
        {
            this.name = name;
        }

    What is the benefit of " this. " ?

    and also why she use "protected" and what is the benefit of it ?

    for (Animal a : animals)

    why she use this "for" and what is the benefit of it ?

    thanx a lot ..and plz I want the answers at nearest time

  2. #2
    Crazy Cat Lady KevinWorkman's Avatar
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    Default Re: I need ur help :|

    Quote Originally Posted by Noni View Post
    thanx a lot ..and plz I want the answers at nearest time
    I was going to type up explanations to your questions, but it would probably take too long for you, so I won't.
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  3. #3
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    Default Re: I need ur help :|

    Not a problem , I want answers today or tomorrow , so help me if u can plz

  4. #4
    Crazy Cat Lady KevinWorkman's Avatar
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    Default Re: I need ur help :|

    Quote Originally Posted by Noni View Post
    Not a problem , I want answers today or tomorrow , so help me if u can plz
    I was being facetious. You should read the link in my signature on asking smart questions. Basically, if you want people to take your question seriously, you should use meaningful post titles (we know you need help, that's why you're here, and generic post titles usually just get ignored), you should use proper grammar and spelling (plz isn't a word), and you shouldn't mention the urgency of your question or your time (otherwise people will assume you think your time is more valuable than the time of others here).

    Also, many of your questions are better answered by a quick google search. Tell us what you find, and we'll go from there.
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  5. #5
    Administrator copeg's Avatar
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    Default Re: I need ur help :|

    The following pages, quickly found using a google search, should answer most of your questions.
    Undertanding Variables
    Using the this keyword
    Controlling Member Access
    The For Statement

  6. #6
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    Default Re: I need ur help :|

    Quote Originally Posted by KevinWorkman View Post
    I was being facetious. You should read the link in my signature on asking smart questions. Basically, if you want people to take your question seriously, you should use meaningful post titles (we know you need help, that's why you're here, and generic post titles usually just get ignored), you should use proper grammar and spelling (plz isn't a word), and you shouldn't mention the urgency of your question or your time (otherwise people will assume you think your time is more valuable than the time of others here).

    Also, many of your questions are better answered by a quick google search. Tell us what you find, and we'll go from there.
    Yes, your talk is true. I am realy sory. thanks for your alert to me

    and I looked for my questions a lot in google but I did not find what I want exactly

  7. #7
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    Default Re: I need ur help :|

    Quote Originally Posted by Noni View Post
    and I looked for my questions a lot in google but I did not find what I want exactly
    What did you find? What are you still confused about? Did you take a look at the links copeg gave you?
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    Default Re: I need ur help :|

    Quote Originally Posted by copeg View Post
    The following pages, quickly found using a google search, should answer most of your questions.
    Undertanding Variables
    Using the this keyword
    Controlling Member Access
    The For Statement
    Thanxxxx a lot

  9. #9
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    Default Re: I need ur help :|

    Quote Originally Posted by KevinWorkman View Post
    What did you find? What are you still confused about? Did you take a look at the links copeg gave you?
    yes , but I don't understand this link

    The For Statement
    The for Statement (The Java™ Tutorials > Learning the Java Language > Language Basics)

    for (Animal a : animals)
    this part in my subject

    why she use this "for" and what is the benefit of it ?

    I don't understand from the link

  10. #10
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    Default Re: I need ur help :|

    The link refers to that syntax as an enhanced for loop. Again, google is your friend.

    There really isn't a "benefit" other than not needing to keep track of indexes or use them to access the Objects in the array. It's a bit of "syntactic sugar" that gives people a shortcut to using indexes or an Iterator (although, the enhanced for is using an Iterator under the hood).
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  11. #11
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    Default Re: I need ur help :|

    If you're unsure after reading the link about Java for loops, do a google search on "for each loops".

  12. #12
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    Default Re: I need ur help :|

    the "for" loop works like this:
    for(at what point loop starts(u have to define a variable beginning) use semicolion to separate it, where the loop ends (u have to define a variable (the same which first time)) |semicolion| and here u have to give a formula how that variable will reach the end point from the beginning)
    but this is very simple sample. Google this and u will find out that this is very useful when u r blanking it.

    example (try it and watch what will happen).

    for(int i=0; i <10; i++){
    System.out.println(i); }
    Last edited by Toggo; January 7th, 2011 at 08:13 PM.