binary tree.c

#include <stdio.h>
#include <stdlib.h>
struct node{
    int data ;
    struct node *left ;
    struct node *right ;
};
struct node* maketree(){
    struct node *p ;
    int info ;
    printf("Enter the info or -1 for null\n");
    scanf("%d", &info) ;
    if(info == -1) return NULL ;
    p = (struct node *)malloc(sizeof(struct node)) ;
    p->data = info ;
    printf("Enter the left child of %d\n",info );
    p->left = maketree() ;
    printf("Enter the right child of %d\n",info );
    p->right = maketree() ;
    return p ;
}
void preorder(struct node *t){
    if(t!=NULL){
        printf("%d->", t->data) ;
        preorder(t->left) ;
        preorder(t->right) ;
    }
}
void postorder(struct node *t){
    if(t!=NULL){
        postorder(t->left) ;
        postorder(t->right) ;
        printf("%d->", t->data) ;
    }   
}
void inorder(struct node *t){
    if(t!=NULL){
        inorder(t->left) ;
        printf("%d->", t->data) ;
        inorder(t->right) ;
    }
}
int main(){
    struct node *root ;
    root = maketree();
    printf("Preorder: ");
    preorder(root) ;
    printf("\n Postorder :");
    postorder(root) ;
    printf("\n Inorder");
    inorder(root) ;
    return 0 ;
}