Separators in array (for a matrix) have different, wrong sizes

Question

Why is it so and how to fix it?

\documentclass{article}

\begin{document}
\[
A = \left ( 
\begin{array}{c|c|c}
\\
C_1 & \cdots & C_q \\
\\
\end{array}
\right )
\]

\end{document}

Answer 1

To get both separators to span the full height of the array, you need to replace the code in the first and third row of the array, viz.

\\

with

& & \\

Actually, adding a single & symbol to row, viz.

& \\

works too.

\documentclass{article}
\begin{document}
\[
A = \left ( 
\begin{array}{c|c|c}
& & \\
C_1 & \cdots & C_q \\
& & \\
\end{array}
\right )
\]
\end{document}