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postFixToTree.c++
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postFixToTree.c++
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#include <bits/stdc++.h>
using namespace std;
class node
{
public:
char data;
node* lchild;
node* rchild;
};
//create new node function
node* createNewNode(char data){
node* tmp = new node;
tmp->data = data;
tmp->lchild = tmp->rchild = NULL;
return (tmp);
}
//code to print in postorderly
void postOrderPrint(node* root)
{
if (root != NULL)
{
postOrderPrint(root->lchild);
postOrderPrint(root->rchild);
cout << root->data << endl;
}
}
//print data in an inorder manner
void inOrderPrint(node* root)
{
if (root != NULL)
{
inOrderPrint(root->lchild);
cout << root->data << endl;
inOrderPrint(root->rchild);
}
}
//print data in a preOrder manner
void preOrderPrint(node* root)
{
if (root != NULL)
{
cout << root->data << endl;
preOrderPrint(root->lchild);
preOrderPrint(root->rchild);
}
}
//Evaluating arithmetic tree.
string evaluateTree(node *root)
{
if (root->lchild == NULL && root->rchild == NULL)
{
string str(1, root->data); //converting the character to string
return str;
}
return evaluateTree(root->lchild) + root->data + evaluateTree(root->rchild);
}
int main()
{
string postFix;
stack<node*> tree;
cout << "Input the postfix expression to be converted to a tree in upperCase: " << endl;
cin >> postFix;
//making the tree from the string
for (int i = 0; i < postFix.length(); i++)
{
if (postFix[i] >= 'A' && postFix[i] <= 'Z')
{
tree.push(createNewNode(postFix[i]));
}else{
node* tmp = createNewNode(postFix[i]);
tmp->rchild = tree.top();
tree.pop();
tmp->lchild = tree.top();
tree.pop();
tree.push(tmp);
}
}
//root is the tree created from the string
node* root = tree.top();
cout << "Printing the tree using postOrder/Postfix: " << endl;
postOrderPrint(root);
cout << "Printing the inorder/Infix form of the tree: " << endl;
inOrderPrint(root);
cout << "Printing the Preorder/Prefix form of the tree: " << endl;
preOrderPrint(root);
cout << "Evaluating the tree: " << endl;
string answer = evaluateTree(root);
cout << answer << endl;
}