\documentclass{bidipresentation}
\usepackage{amsmath,amssymb,amsthm}
\pagestyle{pres}
\usepackage{color, graphicx}
\usepackage{tikz}
\usetikzlibrary{shapes,arrows}
\usepackage{xepersian}
\settextfont{Yas}

\begin{document}
\begin{titlepage}
\centering
\distance{1}
{
\LARGE \bfseries  ساختارهای کنترلی \par
}
\vspace{1.3ex} \large
نام من\\[2ex]اسم دانشگاه \\[2ex]
\today
\distance{2}
\end{titlepage}
% Define block styles
\tikzstyle{block} = [rectangle, draw, fill=blue!20,
text width=6em, text centered, rounded corners, minimum height=1em]
\tikzstyle{line} = [draw=red,draw,very thick]
\tikzstyle{point}=[circle,minimum size=0pt,inner sep=0pt]
\tikzstyle{cloud} = [draw, ellipse,fill=blue!20, node distance=1.2cm,
    minimum height=2em]
\tikzstyle{io} = [trapezium,trapezium left angle=70,trapezium right angle=-70,minimum height=0.5cm, draw, fill=blue!20, 
text width=8.25em, text badly centered, node distance=1.2cm, inner sep=0pt]
\tikzstyle{decision} = [diamond, draw, fill=blue!20, 
text width=2.5em, text badly centered, node distance=1.2cm, inner sep=0pt]
%--------------------------------------------------------------------------------------------- slide #1
\begin{plainslide}[روندنمای شرط]
 \centering
\begin{tikzpicture}[node distance = 1.2cm, auto]
% Place nodes
\node [cloud] (init) {\rl{شروع}};
\node [io,below of=init] (io1) {\rl{عدد مورد نظر  x بخوان}};
\node [block, below of= io1] (pross1) {\rl{abs\_x=x}};
\node [decision, below of=pross1] (id) {x<0};
\node[point,left of=id,xshift=-1.5cm] (p1) {};
\node [block, below of= id] (pross2) {\rl{abs\_x=-x}};
\node [io,below of=pross2] (io2) {\rl{مقدار abs\_x را چاپ کن}};
\node[point, left of=io2,xshift=-1.5cm] (p2) {};
\node [cloud,below of= io2] (stop) {\rl{پایان}};
% Draw edges
\path[line,->] (id)--(p1)--node{نه}(p2)--(io2);
\path [line,->] (init) -- (io1);
\path [line,->] (io1) -- (pross1);
\path [line,->] (pross1) --(id);
%\path [line] (id) |- (io2);
\path [line,->] (id) -- node{بله}(pross2);
\path [line,->] (pross2) -- (io2);
\path [line,->] (io2) -- (stop);
\end{tikzpicture}
\end{plainslide}
%--------------------------------------------------------------------------------------------- slide #2
\begin{plainslide}[روندنمای شرط]
 \centering
\begin{tikzpicture}[node distance = 1.2cm, auto, scale=0.5]
% Place nodes
\node [cloud] (init) {\rl{شروع}};
\node [io,below of=init] (io1) {\rl{عدد مورد نظر  x بخوان}};
\node [block, below of= io1] (pross1) {\rl{abs\_x=x}};
\node [decision, below of=pross1] (id) {x<0};
\node[point,left of=id,xshift=-1.5cm] (p1) {};
\node [block, below of= id] (pross2) {\rl{abs\_x=-x}};
\node [io,below of=pross2] (io2) {\rl{مقدار abs\_x را چاپ کن}};
\node[point, left of=io2,xshift=-1.5cm] (p2) {};
\node [cloud,below of= io2] (stop) {\rl{پایان}};
% Draw edges
\path[line,->] (id)--(p1)--node{نه}(p2)--(io2);
\path [line,->] (init) -- (io1);
\path [line,->] (io1) -- (pross1);
\path [line,->] (pross1) --(id);
%\path [line] (id) |- (io2);
\path [line,->] (id) -- node{بله}(pross2);
\path [line,->] (pross2) -- (io2);
\path [line,->] (io2) -- (stop);
\end{tikzpicture}
\end{plainslide}

\end{document}