Compilare: user.cpp: In function ‘int number(std::pair<int, int>, bool)’: user.cpp:26:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < H[ind].size(); ++i) ^ user.cpp:27:12: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if (H[ind][i].code == xhashing) if (mod) return H[ind][i].nr; ^ user.cpp: In function ‘int main()’: user.cpp:88:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("substr.in","r",stdin); ^ user.cpp:89:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("substr.out","w",stdout); ^ user.cpp:91:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &n, &k); ^ user.cpp:93:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(S+1); ^ /tmp/cc4BgLGG.o: In function `main': user.cpp:(.text.startup+0x6f): warning: the `gets' function is dangerous and should not be used.