Tree Traversals Made Easy!

In this blog, I'm going to discuss one of the easiest ways by which you can traverse a binary tree.

Structure Of Tree

struct node
{
    int data;
    node *right,*left;
    node(int data)
    {
        this->data=data;
        left=right=NULL;
    }
};

Tree traversal 

Pre-order :  Root -> Left -> Right 

void preorder(node* root)
{
    if(root==NULL) // base condition
        return ;
        cout<data<<" "; // print root
    preorder(root->left); // go to left child
    preorder(root->right); // go to right child
}

In-order : Left -> Root -> Right

void inorder(node* root)
{
    if(root==NULL)
        return ;
    inorder(root->left);
    cout<<root->data<<" ";
    inorder(root->right);
}       

Post-order : Left -> Right -> Root 

void postorder(node* root)
{
    if(root==NULL)
        return ;
    postorder(root->left);
        postorder(root->right);
        cout<<root->data<<" ";
}       

Sample Main Function

/*
int main() 
{ 
	node* root = new node(12); 
	root->left = new node(10); 
	root->right = new node(30); 
	root->right->left = new node(25); 
	root->right->right = new node(40); 
	inorder(root);
        preorder(root);
        postorder(root); 
	return 0; 
} 
*/

The above-mentioned approaches are quite similar to each other so if you're able to understand and implement one of them, then others will automatically become easy to understand and implement.

So for 3 different traversals, you don't need to understand 3 different approaches instead you can understand one of the above-mentioned algorithms and the rest will be similar with few minor changes.

Happy Coding!