Compilare: user.cpp: In function ‘int main()’: user.cpp:75:39: warning: array subscript has type ‘char’ [-Wchar-subscripts] while ( s [ i ] > st [ vf ] && st [ vf ] < st [ vf - 1 ] && vf >= 2 ) ^ user.cpp:75:52: warning: array subscript has type ‘char’ [-Wchar-subscripts] while ( s [ i ] > st [ vf ] && st [ vf ] < st [ vf - 1 ] && vf >= 2 ) ^ user.cpp:83:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] st [ ++vf ] = s [ i ]; ^ user.cpp:25:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( IN , "r" , stdin ); ^ user.cpp:26:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( OUT , "w" , stdout ); ^ user.cpp:28:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d" , &V ); ^ user.cpp:30:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%s\n" , s ); ^