Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:11: error: ‘exista’ was not declared in this scope user.cpp:16: error: ‘v’ was not declared in this scope user.cpp:42: error: ‘v’ was not declared in this scope user.cpp:6: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result 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 ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result