Compilare: user.cpp: In function ‘void bkt(int, int)’: user.cpp:52:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(lvl == primes.size()) { ~~~~^~~~~~~~~~~~~~~~ user.cpp: In function ‘void getDiv(int)’: user.cpp:64:9: warning: unused variable ‘val’ [-Wunused-variable] int val = x; ^~~ user.cpp: In function ‘char nextch()’: user.cpp:14:34: 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, MAXBUF, fi); ^