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Thread: Understanding methods in my example code

  1. #1
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    Default Understanding methods in my example code

    Hello everybody,

    I found some old practice material with questions. Almost all of the answers were in the document but nit all. I just want to make this documentation complete for myself and any other people who want to learn more about java.

    The code below is provided by the practice material and the following questions were not anywhere to be found in the documents. I have searched the internet to find resources and learn so I can answer the questions posted below the code.
    I hope you guys can help me to determine if the answers I have found through adapting the knowledge I found on the internet is right.

    package Practice;
    import javax.swing.JOptionPane;
     
    public class Oefening1{
     
    	public static void main(String[] args) {
    		char[] dader = {'A','A','C','A','G','G','C','T'};
     
    		char[] controle = new char[dader.length];
     
    		for(int x = 0;x < controle.length;x++){
    			controle[x] = leesletter();
    		}
     
    		int percentage = vergelijkDNA(dader,controle);
    		JOptionPane.showMessageDialog(null, "Overeenkomst " + percentage + " %",
    				"Uitvoer",JOptionPane.INFORMATION_MESSAGE);
    		System.exit(0);
    	}
     
    	public static char leesletter(){
    		char houder;
    		String temp = JOptionPane.showInputDialog(null,"Voer de letter A G C T in","CSI I",
    				JOptionPane.INFORMATION_MESSAGE);
    		houder = temp.charAt(0); //De eerste letter van de String wordt ingegeven.
     
    		if(houder == 'A'){
    			return houder;
    		}
    		else if(houder == 'G'){
    			return houder;
    		}
    		else if(houder == 'C'){
    			return houder;
    		}
    		else if(houder == 'T'){
    			return houder;
    		}
    		else {
    			return 'F';
    		}
    	}
     
    	public static int vergelijkDNA(char[] a,char[] b){
    		double dperc = 0;
    		double tel = 0;
    		int aantal = a.length;
     
    		for(int x = 0;x < a.length; x++){
    			if(a[x] == b[x]){
    				tel++;
    			}
    		}
     
    		dperc = tel/aantal;
    		System.out.println(tel + " " + aantal);
    		System.out.println(dperc);
    		double tperc = dperc * 100;
    		int perc = (int)tperc;
    		return perc;
    	}
    }

    Question 1: How many methods does this code contain?
    My answer:
    A. 8
    public static void main
    JOptionPane.showMessageDialog
    System.exit
    public static char leesletter (this method is called once in the main method)
    JOptionPane.showInputDialog
    public static int vergelijkDNA (this method is called once in the main method)
    System.out.println(tel + " " + aantal);
    System.out.println(dperc);

    Question 2: How many arrays are created in the main method?
    My answer: 2

    I hope to get some more insight in this matter.

    Thanks in advance!!!


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    Default

    Can anybody please tell me if i am right on this?

  3. #3
    Super Moderator Norm's Avatar
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    Default Re: Understanding methods in my example code

    How many methods does this code contain?
    Is that asking for the use of a method or the definition of a method?
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Understanding methods in my example code

    charAt()?

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    Super Moderator jps's Avatar
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    Default Re: Understanding methods in my example code

    Quote Originally Posted by bodylojohn View Post
    Question 2: How many arrays are created in the main method?
    My answer: 2
    Not what I counted

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    Default Re: Understanding methods in my example code

    Quote Originally Posted by jps View Post
    Not what I counted
    Thank you very much jps..

    I forgot the String[] args in the main decleration.
    so its 3.

    I dont need to count the arrays that are created in the methods that are called in the main . Because those arrays are created in the specific method.

    --- Update ---

    Quote Originally Posted by GregBrannon View Post
    charAt()?
    Thank you graigbrannon.
    I missed that one.
    So the total is 9?

  7. #7
    Super Moderator jps's Avatar
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    Default Re: Understanding methods in my example code

    Quote Originally Posted by bodylojohn View Post
    So the total is 9?
    Hard to say for sure, you never responded to Norm's question...

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    Default Re: Understanding methods in my example code

    Quote Originally Posted by jps View Post
    Hard to say for sure, you never responded to Norm's question...
    Ow I am sorry... I quess I read over this one....

    The question in the practice material literally says this:
    How many methods does this code contain?
    And when I divide the question in:

    How many uses of methods?
    How many definitions of methods?

    Thanks a bunch so far guys. The more I am learning about java the more fun it is becoming!!!!

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