/in/foo.cc: In function 'cyx operator^(cyx, int)':
/in/foo.cc:25:16: warning: unused variable 'j' [-Wunused-variable]
         int i, j; for (i = 1; i <= res.m; i++)
                ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:78:17: warning: suggest parentheses around arithmetic in operand of '^' [-Wparentheses]
     P = (P ^ n0 - 1) * V; Q = (Q ^ n0 - 1) * W;
              ~~~^~~
/in/foo.cc:78:39: warning: suggest parentheses around arithmetic in operand of '^' [-Wparentheses]
     P = (P ^ n0 - 1) * V; Q = (Q ^ n0 - 1) * W;
                                    ~~~^~~