Flow Chart
- Tags
- math
A special graph used to represent an algorithm.
| Element | Shape | Example Text |
|---|---|---|
| Instruction | \text{\tikz \draw (0,0) rectangle (2, 1);} | Print B |
| Decision (yes/no) | \text{\tikz [rotate=45] \draw (0,0) rectangle (1,1);} | if \( x < 5 \) |
| Start/Finish | \text{\tikz \drawrounded corners rectangle (2,1);} | Start |
For example you can visualise Euclid's algorithm as a flow chart in fig:euclid-flow.
\begin{figure}
\centering
\begin{tikzpicture}
\node (start) [draw, rectangle] {Start};
\node (input) [draw, rectangle, below=of start] {Input \( a, b \qquad a \geq b \)}
edge [<-] (start);
\node (letp) [draw, rectangle, below=of input] {Let $P$ = Integer part of \( \frac{a}{b} \)}
edge [<-] (input);
\node (letq) [draw, rectangle, below=of letp] {Let \( q = Pb \)}
edge [<-] (letp);
\node (letr) [draw, rectangle, below=of letq] {Let \( r = a - q \)}
edge [<-] (letq);
\node (ris0) [draw, diamond, below=of letr] {Does \( r = 0 \)?}
edge [<-] (letr);
\node (printb) [draw, rectangle, right=of ris0] {Print $b$}
edge [<-] node [midway,above] {Yes} (ris0);
\node (stop) [draw, rectangle, right=of printb] {Stop}
edge [<-] (printb);
\node (loop) [draw, rectangle, below=of ris0] {Let \( a = b, b = r \)}
edge [<-] node[midway, left] {No} (ris0)
;
\draw [->] (loop.west) -- ++(-1, 0) |- (letp);
\end{tikzpicture}
\caption{Euclids algorithm visualised as a flow chart.}
\label{fig:euclid-flow}
\end{figure}