Assignment 12

Assignment no.:12
Title: Implement Generalized Linked List (GLL) to create and display the book index.

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
typedef struct node
{
	union var
	{
		char data;
		struct node *level_link;
	}info;
	int tag;
	struct node *next;
}node;

int i=1;
char str[20];
int main()
   {
    int ch,flag=0;
    struct node *x=NULL;
    struct node *create();
    void display(node *head, int level);
    do
     {
      printf("\n1.create\n2.diplay\n3.quit");
      printf("\n Enter your choice");
     scanf("%d",&ch);
     if(ch==1)
     flag=1;
      if(flag==1)
         {
     switch(ch)
    {
     case 1:i=1;
            x=create();
     break;
     case 2:printf("index\n");
            display(x,0);
  
     break;
     case 3:break;
     }
     printf("\n Do you want to continue");
     scanf("%d",&ch);
      }
    }while(ch!=3);

  return 0;
  }

struct node *create()
{
	node *create_gll(node *head);
	node *head=NULL;
	int count=0,i;
	printf("\nEnter string:");
	scanf("%s",str);
	for(i=0;str[i]!='\0';i++)
	{
		if(str[i]=='(')
		count++;
		else if(str[i]==')')
		count--;
		else continue;
	}
	head=create_gll(head);
	return(head);
}

struct node *create_gll(node *head)
{
	node *n,*prev, *p=NULL;
	head=NULL;
	while(str[i]!='\0')
	{
		if(str[i]=='(')
		{	
	    n=(node *)malloc(sizeof(node));
	    n->tag=1;
	    n->next=NULL;
	if(head==NULL)
	  head=n;
	else
	prev->next=n;
	prev=n;
	i++;
	n->info.level_link=create_gll(p);
      }
  	else if(str[i]==')')
	{
		i++;
		return(head);
	}
	else
	{
		n=(node *)malloc(sizeof(node));
		n->tag=0;
	    	n->next=NULL;
		n->info.data=str[i];
		if(head==NULL)
		head=n;
		else
		prev->next=n;
		prev=n;
		i++;
	}
     }
  return(head);
}

void display(node *head, int level)
{
	int local=0,i;
	while(head!=NULL)
	{
		if(head->tag==0)
		{
		while((head!=NULL)&&(head->tag==0))
		{
			if(local!=level)
			printf("\t");
			printf("%c",head->info.data);
			head=head->next;
			printf("\n");
		}
	}
	else
	{
		for(i=0;i<level;i++)
		printf("\t");
		++local;
		display(head->info.level_link, local);
		printf("\n");
		--local;
		head=head->next;
	}
    }
}