Compilare: user.cpp: In function ‘void solve()’: user.cpp:18:19: warning: array subscript has type ‘char’ [-Wchar-subscripts] st[p++] = s[i] ; ^ user.cpp: In function ‘int main()’: user.cpp:25:44: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "trompeta.in" , "r" , stdin ) ; ^ user.cpp:26:46: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "trompeta.out" , "w" , stdout ) ; ^ user.cpp:27:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d %d" , &n , &m ) ; ^ user.cpp:28:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%s" , s ) ; ^