Compilare: main.cpp: In function 'void pinex(int, int, int, int, int)': main.cpp:9:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(k == v[x].size()){ ~~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:48:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("farey.in", "r", stdin); ^ main.cpp:49:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("farey.out", "w", stdout); ^ main.cpp:51:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^