Compilare: main.cpp: In function 'int main()': main.cpp:39:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(unsigned int i = st; i <= dr; ++i) ~~^~~~~ main.cpp:28:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(input, "r", stdin); ^ main.cpp:29:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(output, "w", stdout); ^ main.cpp:30:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%s", s); ^