\textbf{Accessing parts of arrays}

\lstinline|C[i-1, j-1]| to access element i, j in C (mxn).
\lstinline|C[i-1]| to access i^{th} row
\lstinline|C[:, j-1]| to access j^{th} column

Assigning to accessed elements, changes them. 

\lstinline|A[m:n:o]| accesses the rows from \lstinline|m|
to \lstinline|n| (excluded) in steps of \lstinline|o|

Similarly, \lstinline|C[m:n:o, p:q:r]|