Program to show Tree Operations like INSERTION, INORDER, PREORDER, POSTORDER,TRAVERSAL

# include
# include 
# include 

struct node
{
struct node *left;
int data;
struct node *right;
}     ;

void main()
{
void insert(struct node **,int);
void inorder(struct node *);
void postorder(struct node *);
void preorder(struct node *);
struct node *ptr;
int will,i,num;
ptr = NULL;
ptr->data=NULL;
clrscr();
printf("Enter the number of Nodes you want to add to the tree.");
scanf("%d",&will);

/* Getting Input */
for(i=0;i {
 printf("Enter the item");
 scanf("%d",&num);
 insert(&ptr,num);
 }

getch();
printf("INORDER TRAVERSAL");
inorder(ptr);
getch();
printf("PREORDER TRAVERSAL");
preorder(ptr);
getch();
printf("POSTORDER TRAVERSAL");
postorder(ptr);
getch();
}



void insert(struct node  **p,int num)
{


if((*p)==NULL)
{       printf("Leaf node created.");
 (*p)=malloc(sizeof(struct node));
 (*p)->left = NULL;
 (*p)->right = NULL;
 (*p)->data = num;
 return;
}
else
{       if(num==(*p)->data)
  {
  printf("
  REPEATED ENTRY ERROR
  VALUE REJECTED");
  return;
  }
 if(num<(*p)->data)
  {
   printf("Directed to left link.");
   insert(&((*p)->left),num);
  }
 else
  {
  printf("Directed to right link.");
  insert(&((*p)->right),num);
  }
}
return;
}


/* Tree Traversal Functions*/
////////////// INORDER (LDR) ////////////

void inorder(struct node *p)
{
 if(p!=NULL)
  {
  inorder(p->left);
  printf("Data :%d",p->data);
  inorder(p->right);
  }
 else
  return;
}

////////////// PREORDER (DLR) ////////////

void preorder(struct node *p)
{
 if(p!=NULL)
  {
  printf("Data :%d",p->data);
  preorder(p->left);
  preorder(p->right);
  }
 else
  return;
}


////////////// POSTORDER (LRD) ////////////

void postorder(struct node *p)
{
 if(p!=NULL)
  {
  postorder(p->left);
  postorder(p->right);
  printf("Data :%d",p->data);
  }
 else
  return;
}

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