View Compilation Error

0_0_22248392_20447.cpp:31:14: error: 'P' was not declared in this scope
   Vector u = P-Q;
              ^
0_0_22248392_20447.cpp:31:16: error: 'Q' was not declared in this scope
   Vector u = P-Q;
                ^
0_0_22248392_20447.cpp:32:20: error: 'w' was not declared in this scope
   double t = Cross(w, u) / Cross(v, w);
                    ^
0_0_22248392_20447.cpp:32:34: error: 'v' was not declared in this scope
   double t = Cross(w, u) / Cross(v, w);
                                  ^
0_0_22248392_20447.cpp:32:37: error: 'w' was not declared in this scope
   double t = Cross(w, u) / Cross(v, w);
                                     ^
0_0_22248392_20447.cpp:33:3: error: expected unqualified-id before 'return'
   return P+v*t;
   ^
0_0_22248392_20447.cpp:34:1: error: expected declaration before '}' token
 }
 ^