View Compilation Error

0_0_26075276_12796.cpp: In function '__int128 read()':
0_0_26075276_12796.cpp:6:34: error: 'isdigit' was not declared in this scope
  while(cc = getchar(),!isdigit(cc))if(cc == -1) return -1;ret = cc-48;
                                  ^
0_0_26075276_12796.cpp:7:34: error: 'isdigit' was not declared in this scope
  while(cc = getchar(), isdigit(cc)) ret = cc-48+ret*10;
                                  ^