Drawing a wheel graph with TikZ

Question

Is there a fast way to add a central vertex connected to all others after drawing the cycle graph using the graph library of the tikz package?
This is what the code currently looks like:
documentclass{article}
begin{document}                                             
usepackage{tikz}
usetikzlibrary{graphs,graphs.standard}

begin{tikzpicture}[scale=0.8,every node/.style={scale=0.8}]
    graph  [nodes={circle,fill=black!25}, edges={black!60, semithick}, clockwise, radius=8em,
    n=9, p=0.3] 
        { subgraph C_n [n=6,m=3,clockwise,radius=2cm] };
end{tikzpicture}
end{document}

ferahfeza · Accepted Answer

Give a name to subgraph and then you can use the vertices. Finally find the center of subgraph and draw from center to each vertices.
documentclass[tikz,margin=3mm]{standalone}

usetikzlibrary{graphs,graphs.standard,calc}
begin{document}
begin{tikzpicture}[scale=0.8,every node/.style={scale=0.8}]
    graph  [nodes={circle,fill=black!25}, edges={black!60, semithick}, clockwise, radius=8em,
    n=9, p=0.3] 
        { subgraph C_n [n=6,m=3,clockwise,radius=2cm,name=A] };
        node at  ($(A 1)!.5!(A 4)$) (C){};
        foreach i in {1,2,...,6}{
        draw (C)-- (A i); }
        draw [fill=black!25](C) circle (0.4em);
end{tikzpicture}
end{document}

ADDENDUM:
According to pgf manual on page 212, you can use mid definition.
documentclass[tikz,margin=3mm]{standalone}

usetikzlibrary{graphs,graphs.standard,calc}
begin{document}
begin{tikzpicture}[scale=0.8,every node/.style={scale=0.8}]
    graph  [empty nodes, nodes={circle,fill=black!25}, edges={black!60, semithick}, clockwise, radius=8em,
    n=9, p=0.3] 
        { subgraph C_n [n=6,m=3,clockwise,radius=2cm,name=A]-- mid};
        node at  ($(A 1)!.5!(A 4)$) (C){1};
        foreach i [count=xi from 2]  in {1,2,...,6}{
        node at (A i){xi}; }
end{tikzpicture}
end{document}

Drawing a wheel graph with TikZ

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