listing graphs continued return st[top]/public boolean isempty(/true if nothing on stackreturn (top =- )//end class stackx ///////////////////////////////////////////////////////////////class vertex public char label/label ( ' 'public boolean wasvisited/public vertex(char lab/constructor label labwasvisited false//end class vertex ///////////////////////////////////////////////////////////////class graph private final int max_verts private vertex vertexlist[]/list of vertices private int adjmat[][]/adjacency matrix private int nverts/current number of vertices private stackx thestack/public graph(/constructor vertexlist new vertex[max_verts]/adjacency matrix adjmat new int[max_verts][max_verts]nverts for(int = <max_vertsj++/set adjacency for(int = <max_vertsk++/matrix to adjmat[ ][ thestack new stackx()/end constructor /public void addvertex(char lab