Compilare: user.cpp: In function ‘int in_hash(char*)’: user.cpp:46:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < H[c].size(); ++ j) ^ user.cpp:47:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (m == strlen(a[H[c][j]]) && strcmp(a[H[c][j]], p) == 0) ^ user.cpp: In function ‘int Sieve()’: user.cpp:86:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘void read()’: user.cpp:137:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d\n", &n, &e, &r, &k); ^ user.cpp:140:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/cczscGE0.o: In function `read()': user.cpp:(.text+0x718): warning: the `gets' function is dangerous and should not be used.