Compilare: user.cpp: In function ‘int main()’: user.cpp:28: warning: comparison between signed and unsigned integer expressions user.cpp:9: warning: unused variable ‘m’ user.cpp:9: warning: unused variable ‘n’ user.cpp:7: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:8: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:13: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result