/in/foo.cc: In constructor 'BinTree::BinTree(char*, char*)':
/in/foo.cc:57:36: error: 'strlen' was not declared in this scope
  int ipre=0, imid=0, len=strlen(pre);
                                    ^
/in/foo.cc: In function 'int main(int, char**)':
/in/foo.cc:166:29: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
  BinTree T("abdecf","dbeacf");
                             ^
/in/foo.cc:166:29: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]