Compilare: user.cpp: In function ‘int main()’: user.cpp:45: warning: unused variable ‘S1’ user.cpp:45: warning: unused variable ‘S2’ user.cpp:45: warning: unused variable ‘S3’ user.cpp:46: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:47: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:48: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:52: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result