well i have this but it doesn't seem to work...

Code:
a=0;
b=0;
int c=mat.numrows();
int d=mat.numcols();

int totallength=mat.numrows()*mat.numcols();

cout << totallength;


for (a=0;a<mat.numrows();a++)
{
	for (b=0;b<mat.numcols();b++)
   {
		temp=mat[a][b];
      for (c; c<0; c--);
       {
         for(d; d<0; d--);
          {
         	temp2=mat[c][d];
         }
      }
   }

   mat[a][b]=temp2;
   mat[c][d]=temp;
}
Basically waht im trying to do is 4 nested for loops, 2 for the beginning and 2 for the end, and store the first one in a temp, store the last one in a temp2 and switch.. but doesnt work.