Compilare: main.cpp: In function 'char next_char()': main.cpp:36:31: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, DIM, stdin); ^ main.cpp: In function 'int main()': main.cpp:55:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("unique.in", "r", stdin); ^ main.cpp:56:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("unique.out", "w", stdout); ^