View Compilation Error

0_0_11472972_961.cpp: In function `void solve()':
0_0_11472972_961.cpp:31: error: `even' undeclared (first use this function)
0_0_11472972_961.cpp:31: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_11472972_961.cpp:31: error: `odd' undeclared (first use this function)