I have two tables, but I can't figure out why it doesn't have vertical line at the right of the table. Could you tell me, where I've made mistake?
First one:
\newline
\begin{center}
\begin{tabular}{||c c c c c c||}
\hline
$\emph{p}$ & $\emph{q}$ & $([\emph{p} \wedge$ & $(\emph{p} \Rightarrow \emph{q]})$ & $\Rightarrow$ & $\emph{q}$ \\ [0.5ex]
\hline\hline
0 & 0 & 0 & 1 & 1\\
\hline
0 & 1 & 0 & 1 & 1\\
\hline
1 & 0 & 0 & 0 & 1\\
\hline
1 & 1 & 1 & 1 & 1\\
\hline
\end{tabular}
\end{center}
Second one:
\newline
\begin{center}
\begin{tabular}{||c c c c c c c c c||}
\hline
$\emph{p}$ & $\emph{q}$ & $\neg$ & $(\emph{p} \vee \emph{q})$ & $\leftrightarrow$ & $(\neg\emph{p}$ & $\wedge$ & $\neg\emph{q})$ \\ [0.5ex]
\hline\hline
0 & 0 & 1 & 0 & 1 & 1 & 1 & 1\\
\hline
0 & 1 & 0 & 1 & 1 & 1 & 0 & 0\\
\hline
1 & 0 & 0 & 1 & 1 & 0 & 0 & 1\\
\hline
1 & 1 & 0 & 1 & 1 & 0 & 0 & 0\\
\hline
\hline
\end{tabular}
\end{center}

*{<num>}{<col spec>}approach to defining yourtabularcolumn specification. In your first instance:|| *{6}{c} ||would help highlight there are 6 columns; your second instance:|| *{9}{c} ||would help highlight there are 9 columns. – Werner Nov 02 '21 at 19:01cccccc||so if you have 6 columns the last one will get || but you only have 5 columns, delete one of the c – David Carlisle Nov 02 '21 at 19:01