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  1. #1
    619snake is offline Member
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    Default Arrays and random number method help!

    I need to create a program, that organizes on an array, random numbers for a marketing company and 5 products. This company wants to do a follow up of the households for these 5 products, vacuum cleaner, toothpaste, grass seed, tv remote and motor oil.

    I created a menu, to select which product will be followed up; the thing is that I want to create an array that collects all this numbers, and organize them in sets of rows of ten elements each. And check if there is a duplicate of any random number, I have this, but I'm stuck:

    If someone could help me; I'd be glad!!

    Java Code:
    public static void main(String[] args) {
            Scanner input = new Scanner( System.in);
            
            int choice;
            int number = 0;
            
            // TODO code application logic here
            
            System.out.println("Please select a product:");
            System.out.println("1 - Toothpaste");
            System.out.println("2 - Vacuum Cleaner");
            System.out.println("3 - Motor Oil");
            System.out.println("4 - Grass Seed");
            System.out.println("5 - Television remote");
            choice = input.nextInt();
            
            if (choice == 1)
            { 
               int[][] houses = new int[38][10];
                for ( int i = 0; i < houses.length; i++)
                {  
                for (int j = 0; j < houses[j].length; j++)
                 {    
                   number = (int) ( 37650 * Math.random() ) + 1;
                   System.out.printf("%5d%8d\n",number, i, j, houses[ i ][ j ]);
                  }
                }
            }
            else if (choice == 2)
            {
                int[][] houses = new int[39][10];
                for ( int i = 0; i < houses.length; i++)
                {  
                for (int j = 0; j < houses[j].length; j++)
                 {    
                   number = (int) ( 38135 * Math.random() ) + 1;
                   System.out.printf("%5d%8d\n",number, i, j, houses[ i ][ j ]);
                 }
                }
            }
    Last edited by 619snake; 02-27-2012 at 01:45 AM.

  2. #2
    Norm's Avatar
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    Default Re: Arrays and random number method help!

    I'm stuck:
    Please explain.

  3. #3
    619snake is offline Member
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    Default Re: Arrays and random number method help!

    When running the code, it does not generate the output, I've tried many ways to create an output that shows a row with 10 elements and show no duplicates of the random numbers

  4. #4
    Norm's Avatar
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    Default Re: Arrays and random number method help!

    it does not generate the output
    Strange.
    I see lots of printlns that should generate some output.

    Are you getting compiler errors that prevent the code from executing?

    Please copy the output and paste it here.

  5. #5
    619snake is offline Member
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    Default Re: Arrays and random number method help!

    the output looks like this, but it is not the way it is required:
    It also shows 370 elements instead of 377, I'm loosing 7 elements

    Please select a product:
    1 - Toothpaste
    2 - Vacuum Cleaner
    3 - Motor Oil
    4 - Grass Seed
    5 - Television remote
    1
    24395 0
    2835 0
    23447 0
    5721 0
    29224 0
    13012 0
    32260 0
    35346 0
    30410 0
    20617 0
    35033 1
    6890 1
    1868 1
    30838 1
    27615 1
    3827 1
    30780 1
    29822 1
    10053 1
    36885 1
    10493 2
    16405 2
    4634 2
    16991 2
    26020 2
    15969 2
    32295 2
    18049 2
    14669 2
    28166 2
    6859 3
    5304 3
    20854 3
    25151 3
    10624 3
    20047 3
    5080 3
    14791 3
    4594 3
    27381 3
    11776 4
    2292 4
    10804 4
    27554 4
    19287 4
    26293 4
    29260 4
    30901 4
    11782 4
    31457 4
    6661 5
    17254 5
    20885 5
    13980 5
    29843 5
    9665 5
    21226 5
    3602 5
    25548 5
    2479 5
    26368 6
    46 6
    35760 6
    12787 6
    13781 6
    5526 6
    15837 6
    14492 6
    7437 6
    13961 6
    15063 7
    36169 7
    15897 7
    22421 7
    16037 7
    36404 7
    9536 7
    30521 7
    31115 7
    24067 7
    28694 8
    3072 8
    9776 8
    28158 8
    33194 8
    3253 8
    30185 8
    29729 8
    2476 8
    28426 8
    27405 9
    2104 9
    24815 9
    20960 9
    32524 9
    28730 9
    8113 9
    32449 9
    10222 9
    5199 9
    31779 10
    22231 10
    2895 10
    17572 10
    6012 10
    1965 10
    16929 10
    23863 10
    21361 10
    18113 10
    3690 11
    22939 11
    15792 11
    10289 11
    5928 11
    25177 11
    1926 11
    13060 11
    735 11
    32955 11
    30914 12
    13597 12
    17782 12
    18683 12
    2358 12
    28418 12
    19046 12
    21756 12
    10758 12
    26135 12
    10302 13
    32457 13
    2268 13
    2148 13
    37441 13
    22252 13
    28561 13
    19642 13
    1138 13
    19472 13
    27821 14
    25514 14
    36926 14
    23069 14
    22954 14
    31291 14
    15062 14
    20920 14
    35082 14
    31555 14
    24721 15
    2206 15
    3310 15
    32618 15
    20213 15
    18918 15
    2819 15
    17319 15
    15849 15
    5199 15
    24893 16
    24916 16
    9343 16
    12342 16
    26070 16
    8772 16
    1273 16
    34371 16
    12174 16
    7676 16
    15024 17
    30601 17
    22949 17
    3251 17
    16240 17
    14660 17
    7588 17
    3191 17
    7779 17
    35506 17
    31961 18
    20807 18
    17801 18
    35571 18
    1683 18
    28623 18
    12018 18
    9639 18
    15787 18
    28657 18
    5216 19
    24052 19
    16035 19
    29228 19
    31071 19
    11926 19
    17035 19
    1894 19
    35701 19
    7952 19
    27877 20
    21705 20
    22067 20
    28217 20
    14880 20
    16432 20
    23321 20
    30701 20
    12485 20
    28402 20
    20235 21
    18801 21
    8074 21
    16106 21
    8864 21
    29753 21
    12283 21
    32513 21
    32147 21
    9459 21
    30925 22
    34702 22
    16664 22
    732 22
    461 22
    5622 22
    4547 22
    6789 22
    6492 22
    6536 22
    16793 23
    25609 23
    31611 23
    30657 23
    34226 23
    17371 23
    28385 23
    2846 23
    31005 23
    16250 23
    14218 24
    25680 24
    14901 24
    7960 24
    15325 24
    8789 24
    16082 24
    12933 24
    30495 24
    14013 24
    34881 25
    29838 25
    26387 25
    21832 25
    33600 25
    4393 25
    30097 25
    13135 25
    24969 25
    24457 25
    11663 26
    19296 26
    19717 26
    14880 26
    30305 26
    17235 26
    26831 26
    4139 26
    3870 26
    29936 26
    21695 27
    8345 27
    6868 27
    30626 27
    14284 27
    30849 27
    33944 27
    26723 27
    7681 27
    35234 27
    24544 28
    5690 28
    16497 28
    27911 28
    4301 28
    7485 28
    22324 28
    2571 28
    36224 28
    221 28
    21467 29
    33688 29
    26430 29
    37068 29
    1838 29
    1082 29
    31472 29
    12513 29
    13474 29
    9637 29
    6993 30
    34078 30
    2257 30
    24117 30
    19854 30
    16146 30
    18170 30
    18858 30
    24448 30
    35948 30
    22719 31
    30956 31
    21570 31
    10481 31
    740 31
    19328 31
    35656 31
    28874 31
    8105 31
    36375 31
    21433 32
    25247 32
    36727 32
    31430 32
    21520 32
    19869 32
    22334 32
    30721 32
    2216 32
    27003 32
    17368 33
    18134 33
    33531 33
    21074 33
    28321 33
    33618 33
    32225 33
    23532 33
    5566 33
    30348 33
    26649 34
    2342 34
    86 34
    29070 34
    14865 34
    31587 34
    33722 34
    12251 34
    13415 34
    28157 34
    10064 35
    28599 35
    35109 35
    34600 35
    26570 35
    26239 35
    29401 35
    13680 35
    19417 35
    29020 35
    25890 36
    28769 36
    14468 36
    9895 36
    11922 36
    12511 36
    12100 36
    17365 36
    9323 36
    1747 36

  6. #6
    Norm's Avatar
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    Default Re: Arrays and random number method help!

    Did you really count all those lines?
    If you added an extra value to the printout the computer would count them for you:
    Create an int value out side the loop and print it before (on the same line with) the values that you are printing.
    Increment the variable by one every time it is used.

    Why do you expect 377 lines to print?
    I'd expect 380. 38*10
    Last edited by Norm; 02-27-2012 at 02:03 AM.

  7. #7
    619snake is offline Member
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    Default Re: Arrays and random number method help!

    ok, the thing is that I did not count all those lines, I'd expect 377 lines, because I need to generate 1% random numbers of the quantity of households for each product. but I really don't know if it is possible to create or modify this array to make it display 10 elements per row... and eliminate any duplicates

  8. #8
    Norm's Avatar
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    Default Re: Arrays and random number method help!

    With the looping it will print 380 lines.

    Before you write any more code you need to make a design of what the code will do. Make a list of the steps that the program needs to do to solve your problem.
    When you get the list of steps, then work on writing the code for each step.

    possible to create or modify this array to make it display 10 elements per row
    Don't use the "\n" newline in the printf until you have all the elements you want on a line.
    You could use the println() method to go to a new line when the current line is full.

  9. #9
    619snake is offline Member
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    Default Re: Arrays and random number method help!

    Thanks a lot Norm!! I got all the elements in blocks :) the only thing I need to do now is to remove any duplicate number... which seems a bit troublesome, but I think I can do it

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