int* m = new int [d1*d2];
ptr1 = m;
ptr2 = m + (d2*(d1-1));
if ( *ptr1 != *ptr2){
temp = ptr2;
ptr2 = ptr1;
ptr1 = temp;
}
ptr1 +=d2;
ptr2 -= d2;
In order to do
From
4 1
3 7
5 2
To
5 2
3 7
4 1
This is what i've came up with so far which is pretty much nothing. I'm having problems with finding what kind of a loop would fit in.
Just reverse the whole thing and then reverse each row:
row/col representation:
4 1 => 2 5 => 5 2
5 2 1 4 4 1
actual layout of m:
4 1 5 2 => 2 5 1 4 => 5 2 4 1
m[x + cols*y], so you can reverse each of those rows.
You need two loops, one for the rows that you want to flip, and then to flip each element on that row. So int row runs from 0 to 2, and int column runs from 0 to 1, when flipping your 3x2 matrix.
Better ways have been described in the previous answers. So my answer will address why nothing changed in your output. You were swapping pointers not values. You want to do:
temp = *ptr2;
*ptr2 = *ptr1;
*ptr1 = temp;
--ptr2;
++ptr1;
std::swap(*ptr1, *ptr2). That makes it far clearer what you are trying to do.