Compilare: user.cpp:5: warning: non-local variable ‘<anonymous struct> a’ uses anonymous type user.cpp:5: warning: non-local variable ‘<anonymous struct> b’ uses anonymous type user.cpp:5: warning: non-local variable ‘<anonymous struct> c’ uses anonymous type user.cpp:5: warning: non-local variable ‘<anonymous struct> d’ uses anonymous type user.cpp: In function ‘int main()’: user.cpp:18: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:18: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result