deletion in AVL tree is not working properly in C - c

Question

if i input 15,7,22,3 into this AVL tree, and then i delete 22, the tree then displays only 15. what happened to 7 and 3?? also when i enter the data in this particular order -> 15,7,3,22 and then i delete 22, the program then seems to work fine, i get 15,7 and 3 as my output which is fully balanced. this is very strange. please help me out.
#include <stdio.h>
#include <stdlib.h>
struct node
{
int data;
struct node *left;
struct node *right;
int height;
};
struct node *tree=NULL;
int height(struct node *tree)
{
if(tree==NULL)
return -1;
else{
int lh=height(tree->left);
int rh=height(tree->right);
if(lh>rh)
return 1+lh;
else
return 1+rh;
}
}
int max(int a,int b)
{
return ((a < b)?b:a);
}
int getbalance(struct node *tree)
{
if(tree==NULL)
return 0;
return (height(tree->left)-height(tree->right));
}
struct node *rr(struct node *y)
{
struct node *x,*t2;
x=y->left;
t2=x->right;
x->right=y;
y->left=t2;
return x;
};
struct node *ll(struct node *x)
{
struct node *y,*t2;
y=x->right;
t2=x->left;
y->left=x;
x->right=t2;
return y;
};
struct node *newNode(int val)
{
struct node *ptr;
ptr=(struct node *)malloc(sizeof(struct node));
ptr->data=val;
ptr->left=ptr->right=NULL;
ptr->height=1;
return ptr;
};
struct node *create(struct node *tree,int val)
{
if(tree==NULL)
return newNode(val);
else if(val < tree->data)
tree->left=create(tree->left,val);
else if(val > tree->data)
tree->right=create(tree->right,val);
else
{
printf("\n duplicate value ignored");
return tree;
}
tree->height=1+max(height(tree->left),height(tree->right));
int balance=getbalance(tree);
if(balance>1 && val<tree->left->data)
return rr(tree);
else if(balance<-1 && val>tree->right->data)
return ll(tree);
else if(balance>1 && val>tree->left->data)
{
tree->left=ll(tree->left);
return rr(tree);
}
else if(balance<-1 && val<tree->right->data)
{
tree->right=rr(tree->right);
return ll(tree);
}
return tree;
};
struct node *inordersuccesor(struct node *tree)
{
struct node *ptr;
ptr=tree;
while(ptr->left!=NULL)
{
ptr=ptr->left;
}
return ptr;
}
struct node *delnode(struct node *tree,int val)
{
if(tree==NULL)
return 0;
else if(val<tree->data)
tree->left=delnode(tree->left,val);
else if(val>tree->data)
tree->right=delnode(tree->right,val);
else
{
struct node *temp;
if(tree->left==NULL)
{
temp=tree->right;
free(tree);
return temp;
}
else if(tree->right==NULL)
{
temp=tree->left;
free(tree);
return temp;
}
else
{
temp=inordersuccesor(tree->right);
tree->data=temp->data;
tree->right=delnode(tree->right,temp->data);
}
}
int balance=getbalance(tree);
if(balance==2 && getbalance(tree->left)>=0)
return rr(tree);
else if(balance==2 && getbalance(tree->left)==-1)
{
tree->left=ll(tree->left);
return rr(tree);
}
else if(balance==-2 && getbalance(tree->right)<=-0)
return ll(tree);
else if(balance==-2 && getbalance(tree->right)==1)
{
tree->right=rr(tree->right);
return ll(tree);
}
return tree;
};
void display(struct node *tree)
{
if(tree!=NULL)
{
display(tree->left);
printf("\t%d",tree->data);
display(tree->right);
}
}
int main()
{
int val,option;
do{
printf("\n 1. create");
printf("\n 2. display");
printf("\n 3. find height");
printf("\n 4. balance factor");
printf("\n 5. delete node");
printf("\n 6. exit\n");
scanf("%d",&option);
switch(option)
{
case 1: printf("\n enter val: ");
scanf("%d",&val);
tree=create(tree,val);
break;
case 2: display(tree);
break;
case 3:
printf("\n height [%d]\n",height(tree));
break;
case 4:
printf("\n balance factor = [%d]",getbalance(tree));
break;
case 5:
printf("\n delete node: ");
scanf("%d",&val);
delnode(tree,val);
break;
}
}while(option!=6);
}