hotel bill in c.

#include<stdio.h>
#include<conio.h>
#include<windows.h>
void bill(char name[], char add[], int o[],char *s[],int p[]);
void main()
{
int i,o[10],p[]={40,60,55,85,95,90,130,25,20,10};
char *s[]={"Rice       ","Fried Rice  ","Sahi Paneer  ","Chicken Kosa  ","Chicken Kabab","Chilli Chicken","Mutton Kosa","Salad       ","Soft Drinks","Sweets        "};
char name[20],add[20];
char a,b;
printf("\t ****************WELCOME TO HOTEL LOVELY***************** \n");
printf("\t\t\tNH-1, PHAGWARA, PUNJAB\n");
printf("\t\t\t MOBILE-+91-9872300000\n");
printf("\n\t Enter Your Name:\t ");
gets(name);
printf("\t Enter Your Address:\t");
gets(add);
printf("\n\t **** DEAR CUSTOMER, TODAY WE HAVE SPECIALY ITEM FOR YOU ****\n\n");
printf(" \t ITEMS \t\t\t PRICE\n");
for(i=0;i<10;i++)
{
printf(" %d. %s \t\t %d (Per Plate)\n",i+1,s[i],p[i]);
}
printf("\nDear customer, would you like to give order?(y for yes/ n for no) : ");
scanf("%c",&a);
 if(a=='y'||a=='Y')
 {
 printf("\n\t Your Order ......");
 printf("\n \t Please Select Your Order(Enter Quantity only):\n");

  for(i=0;i<10;i++)
  {
  printf("\n  %d  \t   %s   \t\t   :\t",i+1,s[i]);
  scanf("%d",&o[i]);
  }
 printf("\n\n \t In 10 Minutes, food will be on the Table");
 printf("\n \t Please Wait....!\n");
 printf("\n\n\n\t Want bill, Sir...?(y for yes)\t:\t ");
 scanf(" %c",&b);

  if(b=='y'||b=='Y')
  {
      bill(name,add,o,s,p);
      }
  }
 printf("\n\n\n\t\t Thank You Sir, Visit Again...!");
 printf("\n___________________________________________________DEVELOPED BY BIKASH THAPA\n");
}
 void bill(char name[], char add[], int o[],char *s[],int p[])
      {
          int i,tot=0;
          system("cls");
          printf("\n\t******************WELCOME TO HOTEL LOVELY********************* \n");
 printf("\t\t\t NH-1, PHAGWARA, PUNJAB\n");
 printf("\t\t\t MOBILE-+91-9872350000\n");
 printf("\n\t Customer Name: \t");
 puts(name);
 printf("\t Customer Address: \t");
 puts(add);
  printf("\n\t Your Today's Bill is.....\n");
  printf(" \t\t\t    ITEMS       \t\t\t\t TOTAL");
  printf("\n\t____________________________________________________________________");
   for(i=0;i<10;i++)
   {
    if(o[i]!=0)
    {
    printf("\n\t\t    %s    \t(%d X %d)\t\t    %d",s[i],o[i],p[i],o[i]*p[i]);
    }
   }
   printf("\n\t____________________________________________________________________");
    for(i=0;i<10;i++)
    {
    tot=tot+o[i]*p[i];
    }
  printf("\n\t Your Total Billing amount is\t:\t\t\t    %d\n",tot);
}

#Program to insert data and display data using double linked list

#include<stdio.h>
#include<conio.h>
struct node
{
    int data;
    struct node *p;
    struct node *n;
};
struct node *first=NULL;
struct node *last=NULL;
void insert(void);
void displayB(void);
void displayL(void);
void main()
{
    while(1)
    {
    int ch;
    printf("1.To insert Data\n");
    printf("2.To Display Data From beginning\n");
    printf("3. To Display Data from End\n");
    printf("4. Exit\n");
    printf("Enter Choice\n");
    scanf("%d",&ch);
    switch(ch)
    {
    case 1:
        insert();
        break;
    case 2:
        displayB();
        break;
    case 3:
        displayL();
        break;
    case 4:
        exit(1);
        break;
    default:
        printf("Wrong input\n");
        break;
    }
    }
}
void insert(void)
{
    int v;
    printf("Enter value\n");
    scanf("%d",&v);
    struct node *ptr;
    ptr=(struct node *)malloc(sizeof(struct node));
    ptr->data=v;
    if(first==NULL)
    {
        ptr->p=NULL;
        ptr->n=NULL;
        first=last=ptr;
    }
    else{
               ptr->p=last;
        ptr->n=NULL;
        last->n=ptr;
         last=ptr;
    }
}
void displayB()
{
    struct node *ptr;
    ptr=first;
    printf("\nThe list of Data from Beginning are;");
    while(ptr->n!=NULL)
    {
        printf("\n%d",ptr->data);
    ptr=ptr->n;
    }
    printf("\n%d\n",ptr->data);

}
void displayL(void)
{
    struct node *ptr;
    ptr=last;
    printf("\nThe list of data from Last are:");
    while(ptr->p!=NULL)
    {
        printf("\n%d",ptr->data);
        ptr=ptr->p;
    }
    printf("\n%d\n",ptr->data);
}

//program to add node in a link list
#include<stdio.h>
#include<conio.h>
struct node
{
int data;
struct node *next;
};
struct node *first=NULL;
struct node *last=NULL;
void insert(int);
void display(void);
void main()
{
int v,ch;
while(1)
{
printf("1. Insert Data\n");
printf("2. Display List \n");
printf("3. Exit\n");
printf("Enter your choice\n");
scanf("%d",&ch);
switch(ch)
{
case 1:
    printf("Enter Value to insert\n");
    scanf("%d",&v);
    insert(v);
    break;
case 2:
    printf("The list is\n");
    display();
    break;
case 3:
    exit(1);
    break;
default:
    printf("Wrong input");
    break;

}
}
}
void insert(int v)
{
    struct node *ptr;
    ptr=(struct node*)malloc(sizeof(struct node));
    ptr->data=v;
    if(first==NULL)
    {
        first=last=ptr;
        ptr->next=NULL;
    }
    else
    {
        last->next=ptr;
        ptr->next=NULL;
        last=ptr;
    }
}
void display()
{
struct node *ptr;
if(first==NULL)
{
    printf("No Record Found\n");
}
else if(first==last)
    {
        printf("%d\n",first->data);
    }
    else
    {
        for(ptr=first;ptr!=last;ptr=ptr->next)
        {
            printf("%d\n",ptr->data);
        }
        printf("%d\n",last->data);
    }
}