View Compilation Error

0_0_30186572_20213.cpp: In function 'void getNext(char*)':
0_0_30186572_20213.cpp:14:36: error: 'strlen' was not declared in this scope
  int i = 0, j, po, len = strlen(str);
                                    ^
0_0_30186572_20213.cpp: In function 'void pt()':
0_0_30186572_20213.cpp:34:25: error: 'strlen' was not declared in this scope
  for (i = 0;i < strlen(s);i++) cout << i << "==" << Next[i] << endl;
                         ^
0_0_30186572_20213.cpp: In function 'int main()':
0_0_30186572_20213.cpp:41:30: error: 'memset' was not declared in this scope
   memset(Next, 0, sizeof Next);
                              ^
0_0_30186572_20213.cpp:45:28: error: 'strlen' was not declared in this scope
   int ans = 0,len= strlen(s);
                            ^