Compilare: main.cpp: In function 'int main()': main.cpp:20:15: warning: array subscript has type 'char' [-Wchar-subscripts] while(st[vf] < ch && del){ ^ main.cpp:24:11: warning: array subscript has type 'char' [-Wchar-subscripts] st[++vf] = ch; ^ main.cpp:8:39: 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); ^ main.cpp:9:41: 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); ^