View Compilation Error

0_0_37843292_21358.cpp: In function 'int get_int()':
0_0_37843292_21358.cpp:7:34: error: 'getchar_unlocked' was not declared in this scope
     while ((c = getchar_unlocked()) < '-');
                                  ^
0_0_37843292_21358.cpp:10:34: error: 'getchar_unlocked' was not declared in this scope
     while ((c = getchar_unlocked()) >= '0') n = n * 10 + c - '0';
                                  ^