I want to draw a binary tree like this:
I have come up with the code below, but the size of the circle is too large. I tried to decrease the size, however, failed, can someone tell me how?
\usetikzlibrary{shapes,arrows,positioning}
\usepackage{wrapfig}
\usepackage{graphicx}
\resizebox{.4\textwidth}{!}{\begin{tikzpicture}[
block/.style = {circle, draw,
text width=2em,align=center,radius=.05cm},
line/.style = {draw,thick, -latex'},
node distance=0.9cm and 0.4cm
]
% Place nodes
\node [block] (a) {a};
\node [block, below left of=a,xshift=-1.0cm, yshift=-0.3cm] (b) {b};
\node [block, below right of=a,xshift=1.0cm, yshift=-0.3cm] (c) {c};
% Draw edges
\path [line] (a) -- (b);
\path [line] (a) -- (c);
\end{tikzpicture}}
Best Answer
Following the suggestion in Jake's comments, I replaced radius=0.05cm by something like text width = 0.05cm. Below is your modified code.
You should get the following output.