AVL Tree program in C

#include <stdio.h> #include<malloc.h> typedef enum{FALSE,TRUE}booleanx; struct anode *avlinsert(int,struct anode*,booleanx*); struct anode *avlsearch(struct anode*,int); void avldisplay(struct anode*,int); void avlinorder(struct anode*); struct anode { int info; //data int balance;//balance factor struct anode *lchild; struct anode *rchild; }; void main() { booleanx ht_inc; int info; int choice; system("cls"); struct anode *root=(struct anode*)malloc(sizeof(struct anode)); root=NULL; while(1) { printf("\n1. Insert\n"); printf("\n2. Display\n"); printf("\n3. Return to tree menu\n"); printf("Enter your choice:"); scanf("%d",&choice); switch(choice) { case 1: printf("\n Enter the value to be inserted:"); scanf("%d",&info); if(avlsearch(root,info)==NULL) root=avlinsert(info,root,&ht_inc); else printf("\n Duplicate value ignored\n"); break; case 2: if(root=NULL) { printf("\n Tree is empty\n"); continue; } printf("\n Tree is:\n"); avldisplay(root,1); printf("\n\n"); printf("\n Inorder traversal is:"); avlinorder(root); printf("\n"); break; case 3: return; default : printf("\nWrong choice\n"); }//end of switch }//end of while }//end of main struct anode *avlsearch(struct anode*ptr,int info) { if(ptr!=NULL) if(info<ptr->info) ptr=avlsearch(ptr->lchild,info); else if(info>ptr->info) ptr=avlsearch(ptr->rchild,info); return ptr; }//end of search struct anode *avlinsert(int info,struct anode*pptr,booleanx*ht_inc) { struct anode *aptr; struct anode *bptr; if(pptr==NULL) { pptr=(struct anode*)malloc(sizeof(struct anode)); pptr->info=info; pptr->lchild=NULL; pptr->rchild=NULL; pptr->balance=0 *ht_inc=true; return pptr; } if (info<pptr->info) { pptr->lchild=avlinsert(info,pptr->lchild,ht_inc); if(*ht_inc==true) { switch(pptr->balance) { case 1://right heavy; pptr->balance=0 *ht_inc=false; break; case 0: //balanced pptr->balance=1; break; case -1://left heavy aptr=pptr->lchild; if(aptr->balance==-1) { printf("left to left rotation\n"); pptr->lchild=aptr->rchild; aptr->rchild=pptr; pptr->balance=0; aptr->balance=0; pptr=aptr; } else { printf("left to right rotation\n"); bptr=aptr->rchild; aptr->rchild=bptr->lchild; bptr->lchild=aptr; pptr->lchild=bptr->rchild; bptr->rchild=pptr; if (bptr->balance==1) pptr->balance=-1; else pptr->balance=0; if(bptr->balance==-1) aptr->balance=1; else aptr->balance=0; bptr->balance=0; pptr=bptr; } *ht_inc=false; }//end of switch }//end of if }//end of if if(info>pptr->info) { pptr->rchild=avlinsert(info,pptr->rchild,ht_inc); if (*ht_inc==true) { switch (pptr->balance) { case 1://left heavy pptr->balance=0; *ht_inc=false; break; case 0://balanced pptr->balance=-1; break; case -1: //right heavy aptr=pptr->rchild; if (aptr->balance==-1) { printf("Right to right rotation\n"); pptr->rchild=aptr->lchild; aptr->lchild=pptr; pptr->balance=0; aptr->balance=0; pptr=aptr; } else { printf("Right to left rotation\n"); bptr=aptr->lchild; aptr->lchild=bptr->rchild; bptr->rchild=aptr; pptr->rchild=bptr->lchild; bptr->lchild=pptr; if(bptr->balance==-1) pptr->balance=1; else pptr->balance=0; if(bptr->balance==1) aptr->balance=-1; else aptr->balance=0; bptr->balance=0; pptr=bptr; }//end of else *ht_inc=false; }//end of switch }//end of if }//end of if return pptr; }//end of the function void avldisplay(struct anode*ptr,int level) { int i; if (ptr!=NULL) { avldisplay(ptr->rchild,level+1); printf("\n"); for (i=0; i<level;i++ ) printf(" "): printf("%d",ptr->info); avldisplay(ptr->lchild,level+1); }//end of if }//end of function void avlinorder(struct anode*ptr) { if (ptr!=NULL) { avlinorder(ptr->lchild); printf("%d",ptr->info); avlinorder(ptr->rchild); } }