write a program to implement queue using linked list.

#include<stdio.h>

#include<stdlib.h>

void insertion();

void display();

void create_node();

void deletion();

struct link_list

{

  int data;

  struct link_list *next;

}*start=NULL;

typedef struct link_list node;

node *current,*nnew,*temp;

int main()

 {

  int a;

  char ch;

   do

   {

    printf("\n enter your choice\n\n1->insertion\n2->display\n3->deletion\n");

    scanf("%d",&a);

    switch(a)

      {

      case 2:

      display();

       break;

      case 1:

       {

        insertion();

        }

         break;

      case 3:

       {

        deletion();

       }

        break;

      default:

        printf("wrong choice");

     }

    printf("\n \n press any key to continue and press n to quit->");

    scanf("%s",&ch);

   }while(ch!='n');

 return 0;

 }

void insertion()

{

 int i=0;

 printf("\nhow many nodes you want to create->");

 scanf("%d",&i);

 while(i!=0)

  {

  if(start==NULL)

   {

    create_node();

    start=nnew;

    current=start;

    printf("\tnode inserted successfully\n");

   }

  else

    {

       current=start;

       while(current->next!=NULL)

       {

       current=current->next;

       }

       create_node();

       current->next=nnew;

       current=nnew;

       printf("\tinserted successfully\n");

     }

   i--;

  }

}

void create_node()

{

       int k;

       nnew=malloc(sizeof(node));

       nnew->next=NULL;

       printf("enter the data for this node->");

       scanf("%d",&k);

       nnew->data=k;

}

void display()

{

       int c=0,i;

       current=start;

       while(current!=NULL)

{c++;

       current=current->next;

}

   for(i=0;i<c;i++)

   printf("=====");

   printf("\n");

   current=start;

while(current!=NULL)

{

   printf("%d | " ,current->data);

   current=current->next;

}

   printf("\n");

 for(i=0;i<c;i++)

  printf("=====");

}

void deletion()

{

       int d,i;

       printf("enter how many element you want to delete->");

       scanf("%d",&d);

       for(i=0;i<d;i++)

       {

       if(start==NULL)

       {

              start=NULL;

     printf("Queue is empty\n");

       }

       Else

     {

      temp=start;

      start=start->next;

      free(temp);

      printf("data is deleted");

     }

  }

}

write a programme of stack using linked list.

#include<stdio.h>

#include<stdlib.h>

void display(void);

void push(void);

void pop(void);

struct link_list

{

int data;

struct link_list *next;

}*start=NULL;

typedef struct link_list node;

node *current,*nnew;

int main()

{

int a;

char ch;

do

{

printf("\n enter your choice\n1->push\n2->pop\n3->display\n");

scanf("%d",&a);

switch(a)

{

case 3:

display();

break;

case 2:

       pop();

       break;

case 1:

push();

break;

default:

printf("wrong choice");

}

printf("\n press any key to continue and press n to quit->");

scanf("%s",&ch);

}while(ch!='n');

return (0);

}

void push(void)

{

int i=0,k;

printf("how many elements you want to enter->");

scanf("%d",&i);

while(i!=0)

{

nnew=malloc(sizeof(node));

nnew->next=NULL;

if(start==NULL)

{

printf("enter any integer data->");

scanf("%d",&k);

nnew->data=k;

start=nnew;

current=start;

printf("\t%d pushed successfully\n",start->data);

}

else

{

printf("enter any integer data->");

scanf("%d",&k);

nnew->data=k;

nnew->next=start;

start=nnew;

printf("\t%d pushed successfully\n",start->data);

}

i--;

}

}

void display(void)

{

              current=start;

              printf("\n");

              while(current!=NULL)

              {

              printf("\t%d\n" ,current->data);

              current=current->next;

       }

}

void pop(void)

{

       int count=0;

       printf("how many elements you want to pop->");

       scanf("%d",&count);

       current=start;

       while(count!=0)

       {

       if(start==NULL)

              printf("stack underflow!");

              else

              {

       printf("%d popped successfully\n",start->data);

       current=start;

start=start->next;

free(current);

}

       count--;

}

} 

/*write a program to implement merge sort*/

#include<stdio.h>

#define MAX 50

void mergeSort(int arr[],int low,int mid,int high);

void partition(int arr[],int low,int high);

int main(){

    int merge[MAX],i,n;

    printf("Enter the total number of elements: ");

    scanf("%d",&n);

    printf("Enter the elements which to be sort: ");

    for(i=0;i<n;i++){

         scanf("%d",&merge[i]);

    }

    partition(merge,0,n-1);

    printf("After merge sorting elements are: ");

    for(i=0;i<n;i++){

         printf("%d ",merge[i]);

    }

   return 0;

}

void partition(int arr[],int low,int high){

    int mid;

    if(low<high){

         mid=(low+high)/2;

         partition(arr,low,mid);

         partition(arr,mid+1,high);

         mergeSort(arr,low,mid,high);

    }

}

void mergeSort(int arr[],int low,int mid,int high){

    int i,m,k,l,temp[MAX];

    l=low;

    i=low;

    m=mid+1;

    while((l<=mid)&&(m<=high)){

         if(arr[l]<=arr[m]){

             temp[i]=arr[l];

             l++;

         }

         else{

             temp[i]=arr[m];

             m++;

         }

         i++;

    }

    if(l>mid){

         for(k=m;k<=high;k++){

             temp[i]=arr[k];

             i++;

         }

    }

    else{

         for(k=l;k<=mid;k++){

             temp[i]=arr[k];

             i++;

         }

    }

    for(k=low;k<=high;k++){

         arr[k]=temp[k];

    }

}