Answer by gernot for Adding arrows to a complex contour with Tikz

\documentclass[border=10pt]{standalone}\usepackage{tikz}\usetikzlibrary{decorations.markings}\renewcommand\Re{\mathrm{Re}}\renewcommand\Im{\mathrm{Im}}\tikzset  {decoration=     {markings,      mark=at position 0.5 with {\arrow{stealth}}     },   plain/.style={line width=0.8pt},   arrow/.style={plain,postaction=decorate}  }\begin{document}\begin{tikzpicture}  \draw [help lines,->] (-4,0) -- (4,0) node[below] {$\Re(z)$};  \draw [help lines,->] (0,-1) -- (0,4) node[left] {$\Im(z)$};  \path ( 1,0) node {$\times$} node[below]{$1$};  \path (-1,0) node {$\times$} node[below]{$-1$};  \draw [arrow] (3,0) coordinate (h) arc (0:60:3) coordinate (a);  \draw [arrow] (a) arc(60:120:3) coordinate (b);  \draw [arrow] (b) arc(120:180:3) node [below] {$-R$} coordinate (c);  \draw [plain] (c) -- (-1.5,0) coordinate(d);  \draw [arrow] (d) arc (180:0:.5) coordinate (e);  \draw [arrow] (e) -- (0.5, 0) coordinate (f);  \draw [arrow] (f) arc (180:0:.5) coordinate (g);  \draw [plain] (g) -- (h) node [below] {$R$};  \node [below left] {$O$};  \node at (-1,.8) {$\gamma_1$};  \node at (1,.8) {$\gamma_2$};  \node at (2,3) {$\Gamma_1$};\end{tikzpicture}\begin{tikzpicture}  \draw [help lines,->] (-4,0) -- (4,0) node[below] {$\Re(z)$};  \draw [help lines,->] (0,-4) -- (0,1) node[left] {$\Im(z)$};  \path ( 1,0) node {$\times$} node[above]{$1$};  \path (-1,0) node {$\times$} node[above]{$-1$};  \draw [arrow] (3,0) coordinate (h) arc (0:-60:3) coordinate (a);  \draw [arrow] (a) arc(-60:-120:3) coordinate (b);  \draw [arrow] (b) arc(-120:-180:3) node [above] {$-R$} coordinate (c);  \draw [plain] (c) -- (-1.5,0) coordinate(d);  \draw [arrow] (d) arc (-180:0:.5) coordinate (e);  \draw [arrow] (e) -- (0.5, 0) coordinate (f);  \draw [arrow] (f) arc (-180:0:.5) coordinate (g);  \draw [plain] (g) -- (h) node [above] {$R$};  \node [above right] {$O$};  \node at (-1,-.8) {$\gamma_3$};  \node at (1,-.8) {$\gamma_4$};  \node at (2,-3) {$\Gamma_2$};\end{tikzpicture}\end{document}