LaTex中使用循环连续绘图的例子

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\begin{frame}[fragile]
由 $3$ 个人群可以构成$2^3 = 8$张 \remph{人际关系图},只需分析如下 \remph{$4$}张图即可:\\[12pt] %
\setcounter{maincounter}{0}%设置计数器的值
%每次增加一个值用\stepcounter{maincounter}
\begin{tikzpicture}[line width = 1.0pt]
\pgfmathsetmacro{\h}{1.4}   %两点的水平间距
\pgfmathsetmacro{\v}{1.4}   %两点的垂直间距
% %------------------------------------------------------
\foreach \r/\c in {0/0,2/0,4/0,6/0}
{
\stepcounter{maincounter} %增加计数器的值
\setcounter{secondcounter}{0}%设置计数器的值
%定义原点坐标
\coordinate  (P0) at (\r,\c);

\path (P0)  node[circle,fill=red,inner sep=2pt](a){$a$};
\path (a)+(\h,0 )  node[circle,fill=red,inner sep=2pt](b){$b$};
\path ($ (a)!0.5! (b) $)+(0,\v)   node[circle,fill=red,inner sep=2pt](c){$c$};
\path ($ (a)!0.5! (b) $)+(0,-0.5)   node (T){ $\left( \themaincounter \right) $};
%画直线
\foreach \from/\to in {a/b,a/c,b/c}
{
\stepcounter{secondcounter} %增加计数器的值
\ifthenelse{\value{secondcounter}<\value{maincounter}}{\draw[dashed] (\from) -- (\to)  ;}{\draw[blue] (\from) -- (\to)  ;}
}

}
\end{tikzpicture}
\end{frame}