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Sortind2DArray  RSS feed

 
Greenhorn
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Hi
Please have a look at the below code for sorting a 2D array nad correct me ,. I am not getting a correct output.

 
Marshal
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It seems you used "Quote" tags instead of "Code". I corrected them for you.
 
Sheriff
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I got this output:

Original array{4, 2} {1, 7} {4, 5} {1, 2} {1, 1} {4, 1}

After sorting (1st dimension):{1, 7} {1, 2} {1, 1} {4, 2} {4, 5} {4, 1}

After sorting (second dimension):
{4, 2} {4, 5} {4, 1} {1, 7} {1, 2} {1, 1}

What were you expecting? Your second sort does not sort the second "dimension" (*) but the first in descending order.

* Java doesn't have 2d arrays, but arrays of arrays.
 
muscles wood
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this is the expected output

{{1,1}, {1,2}, {1,7}, {4,1},{4,2},{4,5}}
 
muscles wood
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I tried but couldn't get the expected output
 
Knute Snortum
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This code is comparing and swapping arrays, but do you want to swap arrays, or elements? That is, are you swapping the first "dimension" or the second?
 
muscles wood
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Thtas the question :

Write a method to sort a two-dimensional array using the following header:

public static void sort(int[][] m)
the method performs a primary sort on rows and a secondary sort on columns. For example, the following array

{{4,2}, {1,7}, {4,5},{1,2},{1,1},{4,1}}

Will be sorted to

{{1,1}, {1,2}, {1,7}, {4,1},{4,2},{4,5}}

Then write a tester program (named SortArray2.java) to test your method
 
Knute Snortum
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After sortArrayBubble you have the array correctly sorted in ascending order by the [row][0] element (the first "dimension). But sortArrayBubble1 just reverses that order, so it's not doing what you want.

Check that I'm correct in this.

Now write down what you have in the array after the first, correct sort: I'll start:

[0][0] = 1
[0][1] = 7
[1][0] = 1
[1][1] = 2
etc.

So what elements do you need to sort? What do they all have in common?
 
It is sorta covered in the JavaRanch Style Guide.
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