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Thread: What is the difference between the belows code

  1. #1
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    Default What is the difference between the belows code

    for(int i=0;i<newarray.length;i++)
    {    	
     newarray[i]=cards[i];
     cards=newarray;
    }


     for(int i=0;i<newarray.length;i++)
    {	    	
     newarray[i]=cards[i];
     cards=newarray;
    }
    including parenthises


    why with the second statement the the variable i goes only one time since in the first statement goes 51 times which is newarray.length equal to 51.

    Please help me enyone to understand this.
    Last edited by lulzimfazlija; January 21st, 2011 at 07:11 PM.


  2. #2
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    Default Re: What is the difference between the belows code

    Ok, well there isnt enough information for me to do a run of my own, but I suspect your assumption is incorrect.

    The simple truth is that as long as newarray is 51 indexes long, both loops will run 51 times. The question that you need to ask is: why doesn't it appear that the first runs 51 times?

    Which brings me to the question:
    Do you know the difference between
    int x=0;
    if(x==0)
    System.out.println("Output1");
    System.out.println("Output2");
    and
    int x=0;
    if(x==0)
    {
    System.out.println("Output1");
    System.out.println("Output2");
    }

    The answer has to do with statement blocking. Between any two curly brackets is what is called block code. Whenever a condition is met, a loop is running, a method is called, ect. everything in that block of code (with the exception of code that is run on conditions or if exceptions are thrown) will run. All code after the block obviously runs after the block. Now, if no curly brackets are added to indicate a block, only the first line of code immediately after the condition is called or only the first line of code immediately after the loop declaration runs while the loop runs.

    So, in your above code:
    For the first snippet:
    Only newarray[i]=cards[i]; is ran in the loop. cards=newarray; is consider "outside the scope of the loop" and thus does not run when the loop runs. #1 above is the same as this:
    for(int i=0;i<newarray.length;i++)
    {
    newarray[i]=cards[i];
    }
    cards=newarray;

    For the second snippet:
    Both newarray[i]=cards[i]; and cards=newarray; runs while the loop runs.


    Tell me if that makes sense. If you already know all of this, add more code so we can see the context of your problem. Otherwise, we have no real way to determine what is happening.
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  3. #3
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    Default Re: What is the difference between the belows code

    I'm not sure what your code is supposed to do, as the logic seems pretty wonky.

    But since your question was on syntax, I'll just answer that part:

    Curly brackets denote a block of code, which can be used anywhere a single statement is allowed (source: Expressions, Statements, and Blocks (The Java™ Tutorials > Learning the Java Language > Language Basics))

    Basically, in your first code snippet (where are your code tags?), only the newarray[i] = cards[i] line is happening "inside" the loop. In your second code snippet, both lines are happening "inside" the loop because both lines are inside the curly braces.

    Does that answer your question? I'm not sure what you're talking about with "the variable i goes only one time".

    Edit- Too slow. What aussiemcgr said.
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    Default Re: What is the difference between the belows code

    Quote Originally Posted by KevinWorkman View Post
    Edit- Too slow. What aussiemcgr said.
    pwn'd
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    Default Re: What is the difference between the belows code

    I don't know the type of arrays the OP is using, but it might be better to set the two arrays to be equal after the for loop, rather than doing it every time you add something.

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