# C++ Program to Perform Inorder Non-Recursive Traversal of a Given Binary Tree

If a binary tree is traversed in-order, the left subtree is visited first, then the root and later the right sub-tree. The output the key in ascending order in in_order traversal. This is a C++ Program for Inorder Tree Traversal without Recursion.

## Algorithm

Begin
Declare a structure n.
Declare d of the integer datatype.
Declare a pointer l against structure n.
Declare a pointer r against structure n.
Declare a constructor of structure n.
Pass an integer variable d to parameter.
this->d = d
l = r = NULL
Declare inOrder(struct n *root) function.
Declare a stack s.
Declare a pointer current against structure n.
Initialize n *current = root.
while (current != NULL || s.empty() == false)
while (current != NULL)
s.push(current)
current = current->l
current = s.top()
s.pop()
print current->d.
current = current->r.
insert values in nodes of tree.
Call inOrder(root) function to travern the tree.
End.

## Example

Live Demo

#include<bits/stdc++.h>
using namespace std;
struct n {
int d;
struct n* l;
struct n* r;
n (int d) {
this->d = d;
l = r = NULL;
}
};
void inOrder(struct n *root) {
stack<n *> s;
n *current = root;
while (current != NULL || s.empty() == false) {
while (current != NULL) {
s.push(current);
current = current->l;
}
current = s.top();
s.pop();
cout << current->d << " ";
current = current->r;
}
}
int main() {
struct n* root = new n(6);
root->l = new n(4);
root->r= new n(7);
root->l->l = new n(8);
root->l->r= new n(5);
root->r->l = new n(9);
root->r->r = new n(10);
inOrder(root);
return 0;
}

## Output

8 4 5 6 9 7 10

Updated on: 30-Jul-2019

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