Compilare: main.cpp: In function 'void precalc()': main.cpp:64:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j < primes.size() && primes[j] <= lim[p]) { ~~^~~~~~~~~~~~~~~ main.cpp: In function 'char nxt()': main.cpp:24:31: 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:77:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("asi.in", "r", stdin); ^ main.cpp:78:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("asi.out", "w", stdout); ^