Binary search tree.c

//error on line 142
#include <stdio.h>
#include <stdlib.h>
void menu(void);
struct node{
	int i;
	struct node *lc;
	struct node *rc;
}*root = NULL,*parent;

void insert(void){

	struct node *ptr;
	int item,f=0;
	printf("\nEnter item: ");
	scanf("%d",&item);
	if(root==NULL){
		root = (struct node*)malloc(sizeof(sizeof(struct node)));
		root->i=item;
		root->rc = NULL;
		root->lc = NULL;	
	}
	else{
		ptr = root;
		while(ptr != NULL && f==0){
			if(ptr->i>item){
				parent = ptr;
				ptr = ptr->lc;
			}
			else if(ptr->i<item){
				parent = ptr;
				ptr = ptr->rc;
			}

			else
				f=1;
		}

		if(f==1){

			printf("\nDATA ALREADY EXISIT");
		}
		else{

			ptr = (struct node *)malloc(sizeof(struct node));
			ptr->i = item;
			ptr->rc = NULL;
			ptr->lc = NULL;
			if(parent->i<item)
				parent->rc = ptr;
			else
				parent->lc = ptr;
		}
	}
}

void display(struct node *ptr,int l){
     int i;
     if(ptr != NULL){
            display(ptr->rc,l+5);
            for(i=0;i<l;i++){
               printf("     ");
                              }
            printf("%d\n",ptr->i);
            display(ptr->lc,l+5);
            }

          }

void preorder(struct node *ptr){
	if(ptr !=NULL){
		printf("%d ",ptr->i);
		preorder(ptr->lc);
		preorder(ptr->rc);
	}
}

void inorder(struct node *ptr){
	if(ptr !=NULL){
    inorder(ptr->lc);
	  printf("%d ",ptr->i);
    inorder(ptr->rc);
	}
}

void postorder(struct node *ptr){
	if(ptr !=NULL){
    postorder(ptr->lc);
    postorder(ptr->rc);
 	  printf("%d ",ptr->i);
	}
}

int succ(struct node *temp){
	temp = temp->rc;
	while(temp != NULL){
		if(temp->lc == NULL)
			return temp->i;
		temp = temp->lc;
	}
}

void delete(int item){
	struct node *ptr;
	int  f = 0,d;
	parent = NULL;
	ptr = root;
	while(ptr != NULL&&f==0){
		if(ptr->i>item){
			parent = ptr;
			ptr = ptr->lc;
		}
		else if(ptr->i<item){
			parent = ptr;
			ptr = ptr->rc;
		}

			else
				f=1;
	}
	if(f==0 && ptr==NULL){
		printf("\nItem Not Found");
	}
	else{
		if(ptr->rc==NULL && ptr->lc==NULL){
			if(parent->rc == ptr){
				parent->rc =  NULL;
				free(ptr);
			}
			else{
				parent->lc = NULL;
				free(ptr);
			}
		}
		else if(ptr->lc!=NULL && ptr->rc!=NULL){
			d = succ(ptr);
			delete(d);
			ptr->i = d;
		}
		else{
			if(parent->lc==ptr){
				if(ptr->rc==NULL){
					parent->lc = ptr->rc;
				}
				else{
					parent->lc = ptr->rc;
				}
			}
			else{
				if(ptr->rc==NULL){
					parent->rc = ptr->lc;
				}
				else{
					parent->rc = ptr->rc;
				}
			}
			free(ptr);
		}
	}	

}

void menu(void){
     int op,i;
     printf("\n1 for Insert\n2 for Display\n3 for Preorder\n4 for Inorder\n5 for Postorder\n6 for Delete\n7 for Exit");
     printf("\nEnter Choice: ");
     scanf("%d",&op);
     switch(op){
                case 1:
                     insert();
                     menu();     
                break;
                case 2:
                      if(root != NULL)
                        display(root,0);
                      else
                        printf("\nTREE IS EMPTY");
                     menu();
                break;
	            case 3:
                	preorder(root);
                	printf("\n");
                	menu();
           		break;
           		case 4:
               		inorder(root);
                	printf("\n");
                	menu();
           		break;
           		case 5:
                	postorder(root);
                	printf("\n");
                	menu();
                case 6:
                	printf("\nEnter item: ");
                	scanf("%d",&i);
                	delete(i);
                	menu();
                break;
                case 7:
                     return ;
                break;
                default:
                        printf("\nInvalid Option");
                        menu();
                }
  }     
int main(){
    menu();
    return 0;
    }