Question

How can i reverse both full diagonal rows(top left to bottom right and top right to bottom left) of a 2d array? (in java)

eg

21 26 31 36
41 46 51 56
61 66 71 76
81 86 91 96

to:

96 26 31 81
41 71 66 56
61 51 46 76
36 86 91 21

Answer 1

The other algorithm didn't work?

Answer 2

only reversed the corners, not the full diagonal row

Answer 3

Hmm, it works fine for me, testing it out with your values and different-sized arrays.

Answer 4

hmmmmm, weird sorry. do you mind posting it again? (im on a different computer)

Answer 5

Sure, code is:

/**
* Method that inverts diagonals
*
* @param array
*/
public static void reverseDiagonals(int array[][]){
for(int i = 0; i < array.length / 2; i++){ // We only need to go through half the array
int j = array[0].length - 1; // This variable will work the array backwards
int temp = array[i][i]; // This will keep temporary value
array[i][i] = array[j - i][j - i];
array[j - i][j - i] = temp;
temp = array[i][j - i];
array[i][j - i] = array[j - i][i];
array[j - i][i] = temp;
}
}

Answer 6

thank you so much, very much appreciated (works of course)