Program for various operations of Binary Search Tree

Programs for the various operations of a binary search tree. Really lengthy program, but its not so bad if you know the logic. Comment below if you need help

#include<stdio.h> #include<stdlib.h> #define max(A,B) (((A)>(B))?(A):(B)) struct node { int data; struct node *rc,*lc; }*newn,*ptr=NULL,*pre=NULL,*root=NULL,*succ=NULL; void ins(); void del(int); void inorder(struct node *temp); void preorder(struct node *temp); void postorder(struct node *temp); void display(struct node*); void trav(); int height(struct node*); int depth(struct node*); int level(struct node*); main() { int ch,r,x,h,l,d; do { printf("\nMenu for BST:\n1.Ins\n2.Del\n3.Traverse\n4.Lvl\n5.Hght\n6.Disp\n"); printf("\nChoice?:"); scanf("%d",&ch); switch(ch) { case 1: ins(); break; case 2: printf("Enter element the element you wish to insert:"); scanf("%d",&x); del(x); break; case 3: display(root); break; case 4:l=level(root); printf("\nthe maximum level of the ttree is:%d",l); break; case 5:h=height(root); printf("\nheight of the tree is:%d",h); break; case 6:display(root); break; case 7:break; default: printf("\nWrong choice\n"); break; } }while(ch!=7); } void ins() { int d,flag=0; ptr=root; printf("\nEnter the element:"); scanf("%d",&d); newn=(struct node*)malloc(sizeof(struct node)); newn->data=d; newn->lc=NULL; newn->rc=NULL; while((ptr!=NULL)&&(flag==0)) { if(d<ptr->data) { pre=ptr; ptr=ptr->lc; } else if(d>ptr->data) { pre=ptr; ptr=ptr->rc; } else { flag=1; printf("Element already exists!"); } } if(ptr==NULL) { if(root==NULL) { root=newn; ptr=root; } else if(pre->data<d) { pre->rc=newn; ptr=pre->rc; } else { pre->lc=newn; ptr=pre->lc; } } } void del(int x) { ptr=root; while(ptr!=NULL) { if(x<ptr->data) { pre=ptr; ptr=ptr->lc; } else if(x>ptr->data) { pre=ptr; ptr=ptr->rc; } else if(ptr->data==x) { if(ptr->lc==NULL&&ptr->rc==NULL) { if(ptr==root) { free(root); root=NULL; break; } else if(pre->lc==ptr) pre->lc=NULL; else if(pre->rc==ptr) pre->rc=NULL; free(ptr); break; } else if(ptr->lc!=NULL&&ptr->rc==NULL) { if(pre->lc==ptr) pre->lc=ptr->lc; else if(pre->rc==ptr) pre->rc=ptr->lc; free(ptr); break; } else if(ptr->lc==NULL&&ptr->rc!=NULL) { if(pre->lc==ptr) pre->lc=ptr->rc; else if(pre->rc==ptr) pre->rc=ptr->rc; free(ptr); break; } else if(ptr->lc!=NULL&&ptr->rc!=NULL) { succ=ptr->rc; if(succ->lc==NULL) { if(pre->lc==ptr) { pre->lc=succ; succ->lc=ptr->lc; } else if(pre->rc==ptr) { pre->rc=succ; succ->rc=ptr->rc; } free(ptr); break; } else { while(succ->lc!=NULL) { pre=succ; succ=succ->lc; } } ptr->data=succ->data; pre->lc=succ->rc; free(ptr); break; } } } if(ptr==NULL) { printf("\nElement absent\n"); } } void postorder(struct node *temp) { if(temp!=NULL) { postorder(temp->lc); postorder(temp->rc); printf(" %d",temp->data); } } void preorder(struct node *temp) { if(temp!=NULL) { printf(" %d",temp->data); preorder(temp->lc); preorder(temp->rc); } } void display(struct node *root1) { int i; if(root1==NULL) printf("Empty tree!"); printf("\nEnter the order\n1:inorder\n2:preorder\n3:postorder\n"); scanf("%d",&i); if(i==1) { printf("\nINORDER:\n"); inorder(root1); } else if(i==2) { printf("\nPREORDER:\n"); preorder(root1); } else { printf("\nPOSTORDER:\n"); postorder(root1); } } void inorder(struct node *temp) { if(temp!=NULL) { inorder(temp->lc); printf(" %d",temp->data); inorder(temp->rc); } } int height(struct node *root) { if(root==NULL) return 0; else return(max(height(root->lc),height(root->rc))+1); } int level(struct node *root) { if(root==NULL) return 0; else return max(height(root->lc),height(root->rc));