Compilare: user.cpp: In function ‘int main()’: user.cpp:52: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:53: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:55: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:57: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘int f(int, int, int)’: user.cpp:8: warning: ‘a’ may be used uninitialized in this function user.cpp:8: warning: ‘b’ may be used uninitialized in this function