View Compilation Error

0_0_15432594_4823.cpp: In function 'void createTrie(char*)':
0_0_15432594_4823.cpp:12:20: error: 'strlen' was not declared in this scope
  int len=strlen(str);
                    ^
0_0_15432594_4823.cpp: In function 'int findTrie(char*)':
0_0_15432594_4823.cpp:37:20: error: 'strlen' was not declared in this scope
  int len=strlen(str);
                    ^
0_0_15432594_4823.cpp: In function 'int main()':
0_0_15432594_4823.cpp:56:31: error: 'memset' was not declared in this scope
     memset(str, 0, sizeof(str));
                               ^