swapping 2 numbers in 2 dimensional array

Pseudo code:

SwapRows(x[size][size], row0, row1, size)
  for col = 0 to size - 1 do
    temp = x[row0][col]
    x[row0][col] = x[row1][col]
    x[row1][col] = temp

Now all you need to do is convert the pseudo code into C++, then test, debug and document it.