Compilare: main.cpp: In function 'int main()': main.cpp:65:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("permutariab.in", "r", stdin); ^ main.cpp:66:45: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("permutariab.out", "w", stdout); ^ main.cpp: In function 'char advance()': main.cpp:14:35: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread (buffer, 1, SIZE, stdin); ^