Compilare: user.cpp: In function ‘void read()’: user.cpp:11: warning: unused variable ‘i’ user.cpp:14: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result user.cpp: In function ‘void write()’: user.cpp:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp: In function ‘void solve()’: user.cpp:24: warning: ‘right’ may be used uninitialized in this function user.cpp:24: warning: ‘left’ may be used uninitialized in this function