Prefix traversal - Prefix expression from Expression Tree

Expression Tree is used to represent expressions. Let us look at how to form prefix expressions from an expression tree

Steps to Write Prefix Expressions from Expression Tree for a*b+c

Let us how to generate the prefix expression from the tree. A prefix expression is generated from the tree as follows:

Consider the root + .
```
Prefix expression created so far = + 
```
Next consider the left subtree a * b.
- For a * b, Consider the root of subtree *.
```
Prefix expression created so far = + *  
```
- For a * b, Consider the left subtree a. Left subtree has only one node a, Hence, first write the same.
```
Prefix expression created so far = + * a 
```
- For a * b, Consider the right subtree b. Right subtree b is just a node.
```
Prefix expression created so far = + * a b
```
Consider the right subtree c . Since the right subtree is just a simple node, there is no more subtrees to be checked
```
Prefix expression created so far = + * a b c
```

Steps to Write Prefix Expressions from Expression Tree for a*b+c

Let us how to generate the prefix expression from the tree. A prefix expression is generated from the tree as follows:

Consider the root + .
```
Prefix expression created so far = + 
```
Next consider the left subtree a * b.
- For a * b, Consider the root of subtree *.
```
Prefix expression created so far = + *  
```
- For a * b, Consider the left subtree a. Left subtree has only one node a, Hence, first write the same.
```
Prefix expression created so far = + * a 
```
- For a * b, Consider the right subtree b. Right subtree b is just a node.
```
Prefix expression created so far = + * a b
```
Consider the right subtree c . Since the right subtree is just a simple node, there is no more subtrees to be checked
```
Prefix expression created so far = + * a b c
```