Compilare: user.cpp: In member function ‘long int Hash::count(mPair)’: user.cpp:27:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<C[dir].size();i++) ^ user.cpp: In member function ‘long int Hash::operator[](mPair)’: user.cpp:38:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(long i=0;i<C[dir].size();i++) ^ user.cpp:40:9: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:86:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maxpal.in","r",stdin); ^ user.cpp:87:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maxpal.out","w",stdout); ^ user.cpp:93:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld",&n); ^ user.cpp:94:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(i=1;i<=n;i++) scanf("%ld",&v[i]); ^