EXPTREE

//Code to generate expression tree from inorder + preorder
using namespace std;
#include <bits/stdc++.h>
int search(char x,string target,int start,int end) {
for(int i=start;i<=end;i++) {
    if(target[i]==x) { return i; }
}
}

class Node{
    public:

        char data;
        Node *left=NULL;
        Node *right = NULL;
        Node(char value) { data=value; }
};

class ExpTree {
    public:
        Node* root = NULL;
        Node* buildTree(string preorder,string inorder,int startIndex,int endIndex) {
            static int preIndex=0;
            if(preIndex>=inorder.length()) { return NULL; }
            if(startIndex>endIndex) {return NULL; }

            Node* tempnode = new Node(preorder[preIndex++]);
              cout<<"PreIndex is: "<<preIndex<<endl;
            cout<<"Node value is : "<<tempnode->data<<endl;
            if(startIndex==endIndex) {
                //Ie. this node has no children, just return it
                return tempnode;
            } else {
                cout<<"Element is: "<<tempnode->data<<endl;
                int splitIndex = search(tempnode->data,inorder,startIndex,endIndex);
                cout<<"Split index is: "<<splitIndex<<endl;
                tempnode->left = buildTree(preorder,inorder,startIndex,splitIndex-1);
                tempnode->right = buildTree(preorder,inorder,splitIndex+1,endIndex);
                return tempnode;
            }
        }
         void inorder(Node* node) {
         //   cout<<node->data<<endl;
           //// cout<<node->right->data<<endl;
           // return;
           if(node==NULL) { return; }
            inorder(node->left);
            cout<<node->data<<"";
            inorder(node->right);
        }
         void postorder(Node* node) {
         //   cout<<node->data<<endl;
           //// cout<<node->right->data<<endl;
           // return;
           if(node==NULL) { return; }
            postorder(node->left);
             postorder(node->right);
            cout<<node->data<<"";

        }

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

};
int main() {
    ExpTree tree;
    string inorder = "DBEAFC";
    string preorder = "ABDECF";
    tree.root = tree.buildTree(preorder,inorder,0,5);
    tree.inorder(tree.root);
}