View Compilation Error

0_0_37447947_16972.cpp: In function 'int main()':
0_0_37447947_16972.cpp:88:69: error: 'head1' was not declared in this scope
    dfn[i] = low[i] = color[i] = viscol[i] = in[i] = f[i] = vis[i] = head1[i] = head2[i] = 0;
                                                                     ^