View Compilation Error

0_0_16263366_17895.cpp: In function 'int judge(char*, char*)':
0_0_16263366_17895.cpp:14:28: error: 'strlen' was not declared in this scope
  int len_from = strlen(from);
                            ^
0_0_16263366_17895.cpp: In function 'int main()':
0_0_16263366_17895.cpp:48:31: error: 'memset' was not declared in this scope
   memset(node, 0, sizeof(node));
                               ^
0_0_16263366_17895.cpp:67:30: error: 'strcpy' was not declared in this scope
     strcpy(node[cnt].col, tmp);
                              ^