View Compilation Error

0_0_33194034_10322.cpp: In function 'int scan_int()':
0_0_33194034_10322.cpp:8:22: error: 'getchar_unlocked' was not declared in this scope
  while ((c = getchar()) < '0') {}
                      ^
0_0_33194034_10322.cpp:10:22: error: 'getchar_unlocked' was not declared in this scope
  while ((c = getchar()) >= '0') {
                      ^