documentclass{article}

begin{document}

begin{tabular}{cc|c}
a & b & xx \
c & d & xx \ hline
e & f & yy \
g & h & yy
end{tabular}

end{document}

documentclass{article}
usepackage{multirow}
begin{document}

begin{tabular}{cc|c}
a & b & multirow{2}{*}{xx} \
c & d & \ hline
e & f & multirow{2}{*}{yy} \
g & h &
end{tabular}

end{document}