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Thread: calling class in other class not working

  1. #1
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    Default calling class in other class not working

    hi there
    i have this class here:
    public class UsernameArrayHolder {
    	public String[] UsernameArrayHolder()  { //need identifier
    		  String[]		UsernameArray	=	{"user1","user2","user3"};				//variable til at holde login navn
     
    		  return UsernameArray;
     
    	}
    }
    and i have one like that but just for password.
    when i try to call it in my other class like this:
     
    import java.util.*;
    public class Login2Darray
     
    {
        public static void main(String [] args){
     
    		  String[] usernameInfo=UsernameArrayHolder.UsernameArray; // i call the other class
     
    		  int i = 0;
     
     
     
    		  Scanner sc=new Scanner(System.in);
     
            System.out.println("Username: ");
     
               String UsernameInput = sc.next();
     
    		  System.out.println("Password: ");
     
               String PasswordInput = sc.next();
     
     
     
    				for (i=0; i<UsernameArray.length; i++){
     
    					if((UsernameInput.equals(UsernameArray[i]) && PasswordInput.equals(PasswordArray[i]))){
     
    								System.out.println("You are logged in");
    								//skriv i værdi til tekst fil
    								i = UsernameArray.length;
    					}	
    				}//end of for loop
     
        }
    }

    the problem is it doesn't seem to work. am i calling it right? and if not how am i supposed do?


  2. #2
    Super Moderator pbrockway2's Avatar
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    Default Re: calling class in other class not working

    Rather than "it doesn't seem to work" it's better to say what you did and what happened when you did that. Eg that you compiled a program and recieved some particular compiler message.

    Remember that you don't call classes, you call methods. And methods are, typically, methods of a particular instance of a class. So, in your main() method first create an instance of the UsernameArrayHolder class using "new", then call the method you want as a method of that particular instance. It is possible to have methods that "belong" in some sense to a class rather than to a specific instance: socalled static methods, but these are best avoided to begin with.

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    Default Re: calling class in other class not working

    so i should make it like this: when i call my method?

    UsernameArrayHolder username = new UsernameArrayHolder();
    PasswordArrayHolder password = new PasswordArrayHolder();
    username.UsernameArrayHolder();
    password.PasswordArrayHolder();

    but when i do that it still says it can't find my UsernameArray :s

  4. #4
    Super Moderator pbrockway2's Avatar
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    Default Re: calling class in other class not working

    What is the code, and what is the compiler message? You have introduced the PasswordArrayHolder class right out of the blue. Work one step at a time.

    Also I notice you have a UsernameArrayHolder() method in the UsernameArrayHolder class. This is confusing at best. If it supposed to be a method call it something else and start it with a lower case letter. If it is supposed to be a constructor then remember that it doesn't return anything.

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    Default Re: calling class in other class not working

    it is suppose to be a constructer call because I want to be able to use the entire array. but i have no idea how to make that call :S

  6. #6
    Super Moderator pbrockway2's Avatar
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    Default Re: calling class in other class not working

    OK. But if it is a constructor then it does not return anything. Some other method of the class will be used to return whatever it is you want to return.

    Are you using a textbook? Because defining classes and using the constructors and methods they define should be explained in detail with examples.

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