Compilare: user.cpp: In function ‘int main()’: user.cpp:31:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("minlcm.in", "r", stdin); ^ user.cpp:32:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("minlcm.out", "w", stdout); ^ user.cpp:42:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &test); ^ user.cpp:44:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:45:52: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (int i = 1; i <= n; ++i) { scanf("%d", &a[i]); viz[a[i]] = 1; } ^ user.cpp:23:27: warning: ‘x2’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (!a || !b) return a + b; ^ user.cpp:47:11: note: ‘x2’ was declared here int x1, x2; ^ user.cpp:23:27: warning: ‘x1’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (!a || !b) return a + b; ^ user.cpp:47:7: note: ‘x1’ was declared here int x1, x2; ^