View Compilation Error

0_0_2093653_10125.cpp:4: error: expected constructor, destructor, or type conversion before ';' token
0_0_2093653_10125.cpp:5: error: ISO C++ forbids declaration of `valid' with no type
0_0_2093653_10125.cpp: In function `int valid(int, int)':
0_0_2093653_10125.cpp:6: error: `n' undeclared (first use this function)
0_0_2093653_10125.cpp:6: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_2093653_10125.cpp: In function `int main()':
0_0_2093653_10125.cpp:40: error: `n' undeclared (first use this function)