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Thread: Iterating a String

  1. #1
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    Default Iterating a String

    String String1 = new String();

    String1 = "bubble";


    My method : DisplayLetter(char aChar);



    If I execute
    DisplayLetter(String1.charAt(0));
    DisplayLetter(String1.charAt(1));
    DisplayLetter(String1.charAt(2));
    DisplayLetter(String1.charAt(3));
    DisplayLetter(String1.charAt(4));
    DisplayLetter(String1.charAt(5));

    it will display
    b
    u
    b
    b
    l
    e
    I would like to be able to achieve the above by using a loop:


    for (int count = 0; count < String1.length; count++)
    DisplayLetter(String1.charAt(?));


    Can you advise one correct format.

    rgds.
    Last edited by av8; July 5th, 2011 at 05:04 AM.


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Iterating a String

    In the code for a loop that you posted, what variable is going to start at 0 and increment by one every time thru the loop?

    Does the code you posted compile? length is a method not a variable in the String class

    Java naming conventions: variable names start with lowercase letters: string1 vs String1

    Also I'd recommend that you put a { at the end of the if statement and a } following the last line that you want to be in the loop. Align the ending } with the start of the if statement. Indent the code within the {}s.

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    Default Re: Iterating a String

    I'm getting there slowly. I can have the loop counter as an actual parameter to itererate through a string object

    DisplayLetter(String1.charAt(for (int count= 0; count < aString.length; count++));

    but i'm getting illegal start of expression. What is my error , can any top java guy help on my code above so it runs ok.

    Cheers.

  4. #4
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    Default Re: Iterating a String

    That's an interesting construction of a statement.
    Your previous post was almost there, you just had to put the loop index into the method call.
    Now what have you done?
    What does the API doc for the charAt() method say it takes for an argument?
    Certainly not a for loop.
    You could use an expression of some kind as the argument for charAt() as long as it returned the correct type of value. for loops are not expressions that return values.

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    Default Re: Iterating a String

    Can you advise on the syntax how to put the loop index into the method call.

    Thank you.

  6. #6
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    Default Re: Iterating a String

    Replace the ? with count

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    Default Re: Iterating a String

    Thanks Norm I've tried this and it displays only the last letter e.

  8. #8
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    Default Re: Iterating a String

    I've tried this and it displays only the last letter
    What did you try? I don't see any code.

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    Default Re: Iterating a String

    for(int count = 0; count < aString.length(); count++)
    DisplayLetter(aString.charAt(count));

  10. #10
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    Default Re: Iterating a String

    This is painful. Do I have to ask you for the source line by line?
    You don't show what the value of aString is or the complete output from your program.

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    Default Re: Iterating a String

    Sorry,

    String aString = new String();



    aString = "bubble";

    for(int count = 0; count < aString.length(); count++)
    DisplayLetter(aString.charAt(count));

    the out put is e

  12. #12
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    Default Re: Iterating a String

    For the next lines of code I need to see: The DisplayLetter method.

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    Default Re: Iterating a String

    Execute this code and see what is printed out:
          String aString = "bubble";
          for(int count = 0; count < aString.length(); count++) {
              System.out.println(count + " " + aString.charAt(count)); 
          } // end for(count)

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    Default Re: Iterating a String

    Another scenario

    String String1 = new String();

    String1 = "bubble";

    String1.charAt(0);
    String1.charAt(1);
    String1.charAt(2);
    String1.charAt(3);
    String1.charAt(4);
    String1.charAt(5);

    when I execute the above 6 lines individually the output corresponds to the index value.

    I would like to output all the individual characters using the code below but I do not know what I am missing.... their is no output.

    for (int count = 0; count < String1.length(); count++)
    String1.charAt(count);

  15. #15
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    Default Re: Iterating a String

    for (int count = 0; count < String1.length(); count++) 
      String1.charAt(count);
    vs
    for(int count = 0; count < aString.length(); count++)
       DisplayLetter(aString.charAt(count));
    Why did you remove the call to the DisplayLetter() method?

    The following line returns a char, but what does the compiler do with that returned value?????
    String1.charAt(count);

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    Default Re: Iterating a String

    Thank you Norm for your patience

    for(int count = 0; count < aString.length(); count++)
    {
    DisplayLetter(aString.charAt(count));
    }
    I had missed out the curlys, program works now. thanks again, Goodnight.

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    Default Re: Iterating a String

    Adding the braces made zero difference. Your code should have still worked without them. If it didn't then something else in your code was wrong and you fixed it without realising.
    Improving the world one idiot at a time!

  18. #18
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    Default Re: Iterating a String

    I'm afraid there is a lot of magic going on here.

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    Default Re: Iterating a String

    Did I miss the DisplayLetter method code posting, or is it Top Secret?

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