Compilare: user.cpp: In function ‘int desc(int)’: user.cpp:27:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < pr.size() && pr[i] * pr[i] <= x) { ^ user.cpp: In function ‘int main()’: user.cpp:54:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("joc18.in","r",stdin); ^ user.cpp:55:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("joc18.out","w",stdout); ^ user.cpp:63:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ", &t); ^ user.cpp:66:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ", &n); ^ user.cpp:67:31: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(c, MAX-1, stdin); ^