Program of traversing a binary tree in inorder, preorder and postorder in C++ Programming

#include
#include
#include
struct btree
{
    struct btree *left;
    struct btree *right;
    int no;
};
void postorder(struct btree *trav);
void inorder(struct btree *trav);
void preorder(struct btree *trav);
struct btree * create(struct btree *trav);
main()
{
    struct btree *root=NULL;
    char c;
    clrscr();
    while(1)
    {
        root=create(root);
        cout<<"Do you want to continue : ";
        cin>>c;
        if(c=='n' ||c=='N')
            break;
    }
    cout<"Inoder is    : "

;inorder(root); cout<"Preorder is : ";preorder(root); cout<"Postorder is : ";postorder(root); getch(); } struct btree * create(struct btree *trav) { if(trav==NULL) { trav=new btree; trav->right=NULL; trav->left=NULL; cout<<"Enter the no : "; cin>>trav->no; return(trav); } char choice; cout<<"Enter the left or right child : "; cin>>choice; if(choice == 'r' || choice == 'R') { trav->right=create(trav->right); } if(choice=='l' || choice=='L') { trav->left=create(trav->left); } return(trav); } void inorder(struct btree *trav) { if(trav==NULL) return ; inorder(trav->left); cout<<" "<no; inorder(trav->right); } void preorder(struct btree *trav) { if(trav==NULL) return; cout<<" "<no; preorder(trav->left); preorder(trav->right); } void postorder(struct btree *trav) { if(trav==NULL) return; postorder(trav->left); postorder(trav->right); cout<<" "<no; }