Compilare: main.cpp: In function 'char adv()': main.cpp:14:37: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buf,1,S,stdin); ^ main.cpp: In function 'int main()': main.cpp:36:45: 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:37:47: 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); ^