Complex permutation of elements of an array

[drew99]

I have written two rotation functions that operate on a character array of length equal to a perfect square.
The first rotate n times each odd line to the right and n times each pair line to the left. The second rotates n times each odd column down and n times each pair column up, where n is the numer of current line or column.

Example:
abcde
fghij
klmno
pqrst
uvwxy

Becomes:
eabcd
hijfg
mnokl
tpqrs
uvwxy

And finally:
unoxd
epqcg
hvwfl
mabks
tijry

I would like to reduce everything to a single function, or rather, to a single loop that moves each character in its final position without performing all the steps.
You can do this? Any suggestions?

[eypros]

How many loop you use now? Why don't you show your code to get the whole picture and not talk in the air?

[drew99]

I've tried something similar:

char txt[] = "abcdefghijklmnopqrstuvwxy";
int r = sqrt(strlen(txt));
char tmp[r][r];
int y, z, x = 0;

for(y = 0; y < r; y++)
{
    for(z = 0; z < r - 1; z++)
    {
	if(((z + (y + 1)) % 2) == 1)
	{
          tmp[(r - (z + (y + 1)) - 1)][(z + (y + 1)) % r] = txt[x++];
	}
	else
	{
		tmp[(z + (y + 1) + 1) % r][(z + (y + 1)) % r] = txt[x++];
	}
    }
	tmp[(y + 1) % r][(z + (y + 1)) % r] = txt[x++];
}

It isn't correct.