View Compilation Error

0_0_18283077_22929.cpp: In function 'LL calc(LL)':
0_0_18283077_22929.cpp:18:36: error: 'reverse' was not declared in this scope
  reverse(digit + 1, digit + 1 + tot);
                                    ^
0_0_18283077_22929.cpp:19:23: error: 'memset' was not declared in this scope
  memset(f, 0, sizeof f);
                       ^