View Compilation Error

0_0_28976584_7007.cpp: In function 'void insert(char*)':
0_0_28976584_7007.cpp:39:18: error: 'strlen' was not declared in this scope
  int n = strlen(s);
                  ^
0_0_28976584_7007.cpp: In function 'bool search1(int)':
0_0_28976584_7007.cpp:54:21: error: 'strlen' was not declared in this scope
  int n = strlen(s[x]);
                     ^
0_0_28976584_7007.cpp: In function 'int main()':
0_0_28976584_7007.cpp:81:32: error: 'memset' was not declared in this scope
    memset(tree, 0, sizeof(tree));
                                ^