1 #include <stdlib.h> 2 #include <stdio.h> 3 #include "bin-trees.h" 4 5 static void 6 real_in_order_traverse_no_recurse (tree_ptr root) 7 { 8 struct stack_struct *stack = NULL; 9 tree_ptr current= root; 10 int going_left = 1; /* boolean variable */ 11 while (current != NULL) 12 { 13 while ((current->left != NULL) && going_left) 14 { 15 push (&stack, current); 16 current = current->left; 17 } 18 19 printf ("%d ", current->data); 20 if (current->right) 21 { 22 current = current->right; 23 going_left = 1; 24 } 25 else if (stack != NULL) 26 { 27 current = pop(&stack); 28 going_left = 0; 29 } 30 else 31 current = NULL; 32 } 33 } 34 35 void 36 in_order_traverse_no_recurse (tree_ptr root) 37 { 38 printf ("in-order traversal, without recursion: \n"); 39 real_in_order_traverse_no_recurse (root); 40 printf ("\n"); 41 return; 42 } 43