### Python program to print leaf nodes of the binary search tree

Description:
This program is to print leaf nodes of the binary search tree.
Algo: -
1. Make a class for node in a tree.
2. Form the tree by creating nodes.
3. Traverse the tree.
4. During traversal count check if a node is leaf node and print it.
5. A node is leaf node if both its left and right are none.
Program:
```#A class that represents the individual node of the Binary tree
class node:
def __init__(self, key):
self.left = None
self.right = None
self.data = key

#A function to display the leaf nodes.
def counter(root):
if root:
if root.left==None and root.right==None:
print(root.data)
#First recur the left child
if root.left:
counter(root.left)
#Recur the right child at last
if root.right:
counter(root.right)

def main():

root = node(5)  #root node of the tree
root.left = node(4) #node at left of root
root.right = node(6) #node at right of root
root.left.left = node(10)
root.right.left = node(12)
root.right.right =node(15)
print('      ',root.data)
print('      / \\')
print('   ',root.left.data,'  ',root.right.data)
print('    /   / \\')
print(' ',root.left.left.data,'  ',root.right.left.data,root.right.right.data)
print('The leaf nodes in the tree are = ')
counter(root)

#Driver code
if __name__ == "__main__":
main()```
Output:
5 / \ 4 6 / / \ 10 12 15 The leaf nodes in the tree are = 10 12 15

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