Compilare: main.cpp: In function 'int main()': main.cpp:42:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dr.in","r",stdin); ^ main.cpp:43:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dr.out","w",stdout); ^ main.cpp: In function 'void Next()': main.cpp:71:44: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] std::fread(s, 1, Lim, stdin), u = 0; ^