Compilare: user.cpp: In function ‘int main()’: user.cpp:12:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("plaja.in","r",stdin); ^ user.cpp:13:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("plaja.out","w",stdout); ^ user.cpp:14:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld%ld%ld",&a,&b,&u); ^ user.cpp:15:56: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i=1;i<=u;i++) {scanf("%ld%ld",&um1[i],&um2[i]);} ^ user.cpp:16:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld",&n); ^ user.cpp:20:46: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld%ld%ld%ld",&x1,&y1,&x2,&y2); ^ user.cpp:33:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld",&m); ^ user.cpp:42:46: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld%ld%ld%ld",&x1,&y1,&x2,&y2); ^