Compilare: user.cpp: In function ‘void _read()’: user.cpp:16: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:19: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void solve()’: user.cpp:30: warning: ‘res’ may be used uninitialized in this function user.cpp:58: note: ‘res’ was declared here