Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:7: error: ‘n’ was not declared in this scope user.cpp:7: error: ‘k’ was not declared in this scope user.cpp:7: error: ‘a’ was not declared in this scope user.cpp:7: error: ‘b’ was not declared in this scope user.cpp:5: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:6: 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