Compilare: main.cpp: In function 'char read_ch()': main.cpp:21:33: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(_in_buff, 1, 4096, _fin); ^ main.cpp: In function 'int main()': main.cpp:134:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fibsum.out", "w", stdout); ^