build tree from pre and inorder.cpp

#include <iostream>
#include<queue>
using namespace std;

class node{
    public:
        int data;
        node*left;
        node*right;

        node(int d){
            data = d;
            left = NULL;
            right = NULL;
        }
};

/*void print(node *root){
    if(root==NULL){
        return;
    }
    //Otherwise, print root first followed by subtrees(children)
    cout<<root->data<<" ";
    print(root->left);
    print(root->right);
}

void printIn(node*root){
    if(root==NULL){
        return;
    }
    //Otherwise Left Root Right
    printIn(root->left);
    cout<<root->data<<" ";
    printIn(root->right);
}

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


void bfs(node *root){
    queue<node*> q;
    q.push(root);
    q.push(NULL);

    while(!q.empty()){
        node* f = q.front();
        if(f==NULL){
            cout<<endl;
            q.pop();
            if(!q.empty()){
                q.push(NULL);
            }
        }
        else{
            cout<<f->data<<",";
            q.pop();

            if(f->left){
                q.push(f->left);
            }
            if(f->right){
                q.push(f->right);
            }
        }
    }
    return;
}



/*node* buildTreeFromArray(int *a,int s,int e){
    //Base Case
    if(s>e){
        return NULL;
    }
    //Recursive Case
    int mid = (s+e)/2;
    node* root = new node(a[mid]);
    root->left = buildTreeFromArray(a,s,mid-1);
    root->right = buildTreeFromArray(a,mid+1,e);
    return root;
}*/


node* createTreeFromTrav(int *in,int *pre,int s,int e){
    static int i = 0;
    //Base Case
    if(s>e){
        return NULL;
    }
    //Rec Case
    node *root = new node(pre[i]);

    int index=-1;
    for(int j=s;s<=e;j++){
        if(in[j]==pre[i]){
            index = j;
            break;
        }
    }

    i++;
    root->left = createTreeFromTrav(in,pre,s,index-1);
    root->right = createTreeFromTrav(in,pre,index+1,e);
    return root;
}



int main(){ 
    int in[] = {3,2,8,4,1,6,7,5};
    int pre[] = {1,2,3,4,8,5,6,7};
    int n = sizeof(in)/sizeof(int);

    node*root = createTreeFromTrav(in,pre,0,n-1);
    bfs(root);

    


return 0;
}