Compilare: user.cpp: In function ‘int main()’: user.cpp:52: warning: suggest parentheses around ‘-’ in operand of ‘&’ user.cpp:22: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:23: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:39: warning: ‘j’ may be used uninitialized in this function