Compilare: user.cpp: In function ‘int main()’: user.cpp:8:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] { freopen("sdp.in", "r",stdin); ^ user.cpp:9:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sdp.out", "w",stdout); ^ user.cpp:12:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:14:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i]); ^ user.cpp:16:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &b[i]); ^ user.cpp:70:47: warning: ‘d2’ may be used uninitialized in this function [-Wmaybe-uninitialized] printf("%d %d", -(a2+c2), -(b2+d2)); ^ user.cpp:68:23: warning: ‘d1’ may be used uninitialized in this function [-Wmaybe-uninitialized] printf("%d %d", a1+c1, b1+d1); ^ user.cpp:70:37: warning: ‘c2’ may be used uninitialized in this function [-Wmaybe-uninitialized] printf("%d %d", -(a2+c2), -(b2+d2)); ^ user.cpp:68:23: warning: ‘c1’ may be used uninitialized in this function [-Wmaybe-uninitialized] printf("%d %d", a1+c1, b1+d1); ^ user.cpp:70:47: warning: ‘b2’ may be used uninitialized in this function [-Wmaybe-uninitialized] printf("%d %d", -(a2+c2), -(b2+d2)); ^ user.cpp:68:23: warning: ‘b1’ may be used uninitialized in this function [-Wmaybe-uninitialized] printf("%d %d", a1+c1, b1+d1); ^ user.cpp:70:37: warning: ‘a2’ may be used uninitialized in this function [-Wmaybe-uninitialized] printf("%d %d", -(a2+c2), -(b2+d2)); ^ user.cpp:68:23: warning: ‘a1’ may be used uninitialized in this function [-Wmaybe-uninitialized] printf("%d %d", a1+c1, b1+d1); ^