/in/foo.cc: In function 'int main(int, char**)':
/in/foo.cc:37:20: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'int' [-Wformat=]
  scanf("%s%s",in,af);
                    ^
/in/foo.cc:38:18: error: 'strlen' was not declared in this scope
  long l=strlen(in);
                  ^
/in/foo.cc:39:38: error: invalid conversion from 'char' to 'char*' [-fpermissive]
     BinaryTreeFromOrderings(in, af, l);
                                      ^
/in/foo.cc:13:11: note:   initializing argument 1 of 'TreeNode* BinaryTreeFromOrderings(char*, char*, int)'
 TreeNode* BinaryTreeFromOrderings(char* inorder, char* aftorder, int length)
           ^~~~~~~~~~~~~~~~~~~~~~~