Compilare: user.cpp: In function ‘int main()’: user.cpp:5:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("grupuri.in","r",stdin); ^ user.cpp:6:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("grupuri.out","w",stdout); ^ user.cpp:31:8: warning: ‘c’ may be used uninitialized in this function [-Wmaybe-uninitialized] cout<<c; ^