Compilare: main.cpp: In function 'int main()': main.cpp:10:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("nrdivunique.in", "r", stdin); ^ main.cpp:11:44: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("nrdivunique.out", "w", stdout); ^ main.cpp:12:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for (scanf("%d", &n); n; n--) { ^ main.cpp:14:33: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &a, &b); ^