I’m building a C program to generate a threaded binary tree and then discover the INORDER SUCCESSOR of a specific node. For this, I’m presenting the TBT’s inorder sequence and then asking the user to select which node’s successor should be displayed. I’ve built a function to accomplish this. However, I am not receiving a replacement for the FIRST NODE. Here is the complete schedule:
#include<stdio.h>
#include <stdlib.h>
struct tbtnode {
int data;
struct tbtnode *left,*right;
int lbit,rbit,flag;
int child;
}*root=NULL;
typedef struct tbtnode TBT;
TBT *insuc(TBT *t);
void inorder(TBT *);
void create(TBT *);
void create(TBT *root)
{
int x,op,flag,y;
flag=0;
char ch;
TBT *curr=root;
TBT *q,*p;
do
{
printf("\nCurrent node %d \n\n 1.Left Direction.\n\n2.Right Direction",curr->data);
printf("\nEnter ur choice :");
scanf("%d",&op);
switch(op)
{
case 1: if(curr->lbit==1)
{
printf("Enter left child of %d : ",curr->data);
scanf("%d",&x);
q=(TBT *)malloc(sizeof(TBT));
q->data=x;
q->lbit=q->rbit=1;
q->left=curr->left;
q->right=curr;
curr->left=q;
curr->lbit=0;
q->child=0;
flag=1;
}
else
curr=curr->left;
break;
case 2: if(curr->rbit==1)
{
printf("Enter right child of %d :",curr->data);
scanf("%d",&x);
q=(TBT *)malloc(sizeof(TBT));
q->data=x;
q->lbit=q->rbit=1;
q->left=curr;
q->right=curr->right;
curr->right=q;
curr->rbit=0;
q->child=1;
flag=1;
}
else
curr=curr->right;
break;
}
}while(flag==0);
}
void inorder(TBT *head)
{
TBT *t;
t=head->left;
printf("\n");
while(t->lbit==0)
t=t->left;
while(t!=head)
{
printf(" %d",t->data);
t=insuc(t);
}
}
TBT *insuc(TBT *t)
{
if(t->rbit==0)
{
t=t->right;
while(t->lbit==0)
t=t->left;
return(t);
}
else
return(t->right);
}
void inorder_successor(TBT *head,int x)
{
TBT *t;
t=head->left;
printf("\n");
while(t->lbit==0)
t=t->left;
while(t!=head)
{
t=insuc(t);
if(t->data==x)
{
t=insuc(t);
printf(" %d",t->data);
}
}
}
int main()
{
int op,x,n,i=0,item;
char ch;
TBT *head,*root,*succ; //here head indicates dummy variable
head=(TBT *)malloc(sizeof(TBT));
head->left=head;
head->right=head;
head->lbit=1;
head->rbit=1;
do
{
printf("\n****Threaded binary tree operations****");
printf("\n1)create\n2)inorder\n3)Successor\n4)exit");
printf("\nEnter ur choice: ");
scanf("%d",&op);
switch(op)
{
case 1:
printf("\nEnter Number Of Nodes :");
scanf("%d",&n);
printf("\nEnter root data: ");
scanf("%d",&x);
root=(TBT *)malloc(sizeof(TBT));
root->data=x;
root->lbit=root->rbit=1;
root->child=0;
root->left=head->left;
head->left=root;
head->lbit=0;
root->right=head->right;
for(i=0;i<n-1;i++)
create(root);
break;
case 2:
printf("\nInorder Traversal Is:\n");
inorder(head);
break;
case 3: printf("Enter the node to which successor is to be found\n");
scanf("%d",&item);
inorder_successor(head,item);
break;
case 4:
return(0);
break;
}
}while(op<=4);
return 0;
}
The successor of the last node is 0, yet everything is good. Can anyone assist me in resolving this?