How to write a function (reverseDiagonal) that reverses both diagonals of a two dimensional array (in c++) ?

the original two dimensional array was





21 26 31 36


41 46 51 56


61 66 71 76


81 86 91 96





has to look like this after the function runs





96 26 31 38


41 71 66 56


61 51 46 76


36 86 91 21





if you look between the two ... you can see what is meant by the reverse diagonal part ....





i have pondered over this for a few days and all the different thigns i try fail misserably ...





can anyone help ...???





Please ....

How to write a function (reverseDiagonal) that reverses both diagonals of a two dimensional array (in c++) ?
Here is how you would walk one diagonal. The other is just an simple modification of the first walk.





for (int r =0, c = 0; r %26lt; HEIGHT/2 %26amp;%26amp; c %26lt; WIDTH/2; r++, c++){


swap( array[r][c] , array[HEIGHT - r - 1][ WIDTH - c - 1] );


}





For the second you do essentially the same thing but you would initialize it differently, invert the test for c, and decrement c instead of incrementing it.





for (int r = 0, c = WIDTH -1; r %26lt; HEIGHT/2; c %26gt; WIDTH/2; r++, c--){


swap( array[r][c], array[HEIGHT - r - 1][ WIDTH - c ];


}





You could avoid some of the math by adding two other variables that started at the opposited corner and then moved in. Your test would then be to see when their values crossed.


Here's how that would look with the first loop





for (r_0 = 0, c_0 = 0, r_1 = HEIGHT - 1, c_1 = WIDTH - 1; r_0 %26gt; r_1 %26amp;%26amp; c_0 %26gt; c_1; r_0++, c_0++, r_1--, c_1--){


swap(array[r_0][c_0], array[r_1][c_1]);


}