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Thread: lucky numbers

  1. #1
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    Default lucky numbers

    hi everyone, i have to make a java program that generates "lucky numbers" with arrays
    The finishing result should be this
    1 2 3 4 5 6 7 8 9 10 original
    1 3 5 7 9 remove every second number from the original
    1 3 7 9 remove every 3 number from the above
    1 3 7 remove every 4 number from above

    So far i have the first two but i'm stuck on the other the lines
    for( int j = 0 ; j < start.length; j +=2 ) {
     
    				System.out.print( start[i] + " ");

    this code is for the second line

    if anyone has any ideas they would be much appreciated


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    Default Re: lucky numbers

    I don't see any code that removes anything from an array, so I'm not sure how you plan to proceed from what you have. I believe you should rethink your approach.
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    Default Re: lucky numbers

    i don't know how to remove something from an array, that the problem. And don't really see another approach

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    Default Re: lucky numbers

    I am not certain if this is the best approach, but this is how I would go about it:

    1: Assign a variable some extreme value that it it is very unlikely that the User will ever use.. such as Integer.MAX_VALUE, to be the unsaid value. Thiis will avoid having to make a copy of the array.

    2: When 'removing' a value from the array, simply replace it's index with the previous variable.

    3: When printing the array, first check if the value is the same as the variable assigned in step 1, if it is then do not print it.

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    Default Re: lucky numbers

    i need to now how i can put the output from this code
    for( int j = 0 ; j < start.length; j +=2 ) {

    System.out.print( start[i] + " ");

    into a new for loop.

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    Default Re: lucky numbers

    Quote Originally Posted by robingeldolf View Post
    i need to now how i can put the output from this code
    for( int j = 0 ; j < start.length; j +=2 ) {

    System.out.print( start[i] + " ");

    into a new for loop.
    What do you mean into a new loop? A different loop? A nested loop? Something else?

    And for the record, how I would remove an element from an array is by creating a new array with a length one less than the current array, then copy over every value from the current array except the one you want to remove. You could optimize this if you figured out how many elements you would be removing beforehand.
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