Can't get upper Table border

I need your help in allowing an upper border for a table. many posts have suggested that this should be written:

\begin{tabular}{|c|c|c|}


I have done so but did not get an upper boundary, in my code I have done:

\begin{tabular}{|l||c|c|c|}


• Consider dropping the use of vertical rules, as suggested in booktabs. – Werner Jan 29 '16 at 3:38
• If you aren't using booktabs, use \hline instead of \toprule. – John Kormylo Jan 29 '16 at 3:44

You're looking for

\begin{tabular}[.]{..}
\hline


However, I'd suggest

\usepackage{booktabs}

\begin{tabular}[.]{..}
\toprule


and use all of the associated \midrule and \bottomrule provided by booktabs.