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Thread: Beginner Problem

  1. #1
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    Default Beginner Problem

    Hello, I tried some exercises: Entering a first and a lastname, the return should be the last name in uppercase.
    Example:
    input: John Doe
    output: John DOE

    unfortunately i get a "null null", where is my mistake??

    import java.util.Scanner;
     
    public class A3 {
     
    	static String inData;
    	static String firstname;
    	static String lastname;
     
    	public static void main(String[] args){
     
    		Scanner scan = new Scanner(System.in);
    		inData=scan.next();
    		for(int index=0; index<inData.length(); index++){
    			if(inData.charAt(index) == ' ')
    			{
    				firstname=inData.substring(0, index-1);
    				lastname=inData.substring(index+1, inData.length());
    				lastname=lastname.toUpperCase();
    			}
     
    			else {
    			}
     
    			}
    		System.out.println(firstname + " " + lastname);
    		}
    	}


  2. #2
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    Default Re: Beginner Problem

    Add some more printlns to show what the code is doing and what values you are working with.
    For example print out the value of inData immediately after it is read in:
    System.out.println("inData=" + inData + "<");

    How many lines does your program print out? Can you copy and paste here the full contents of the screen from you test.
    To copy the contents of the command prompt window:
    Click on Icon in upper left corner
    Select Edit
    Select 'Select All' - The selection will show
    Click in upper left again
    Select Edit and click 'Copy'

    Paste here.

  3. #3
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    Default Re: Beginner Problem

    I found the error: I had to use scan.nextLine(); instead of scan.next();
    No it works, thanks for your reply.

  4. #4
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    Default Re: Beginner Problem

    Yes those methods will return different data. Which one to use depends on your application.

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    Default Re: Beginner Problem

    when comparing strings use .equals function or other but not ==

    Keep the code coming!
    Eric

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    Default Re: Beginner Problem

    Quote Originally Posted by ericthegreat View Post
    when comparing strings use .equals function or other but not ==
    Huh? where in the code did he do that?
    Please use [highlight=Java]//code goes here...[/highlight] tags when posting your code

  7. #7
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    Default Re: Beginner Problem

    Where in the posted code does the OP use == to compare Strings?
    Improving the world one idiot at a time!

  8. #8
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    Default Re: Beginner Problem

    Woo I was faster!
    Please use [highlight=Java]//code goes here...[/highlight] tags when posting your code

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