Compilare: user.cpp: In function ‘int main()’: user.cpp:134:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ct.in", "r", stdin); ^ user.cpp:135:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ct.out", "w", stdout); ^ user.cpp: In function ‘void cit(int&)’: user.cpp:14:22: warning: ‘ch’ is used uninitialized in this function [-Wuninitialized] while(!isdigit(ch)) ch = getchar(); ^