set size of table in latex code example

Example 1: change table size latex

\usepackage{graphics}
% ...

\begin{table}
\centering
\resizebox{\columnwidth}{!}{%
\begin{tabular}{r|lll}
\multicolumn{1}{r}{}
& \multicolumn{1}{l}{Heading 1}
& \multicolumn{1}{l}{Heading 2}
& \multicolumn{1}{l}{Heading 3} \\ \cline{2-4}
Row 1 & Cell 1,1 & Cell 1,2 & Cell 1,3 \\
Row 2 & Cell 2,1 & Cell 2,2 & Cell 2,3
\end{tabular}%
}
\end{table}

Example 2: font size table latex

\documentclass{article}
\usepackage{graphicx}
\begin{document}

\begin{table}
\resizebox{\textwidth}{!}{%
  \begin{tabular}{cc}
    Knuth & Lamport
  \end{tabular}}
\end{table}

\end{document}