Quick sort

The following is a program to implement quick sort. If you have any doubts, please let me know.

#include<stdio.h>

void quicksort(int [50],int,int);

main()

{

  int a[50],n,i;

  printf("\nEnter size of the array: ");

  scanf("%d",&n);

  printf("Enter the elements: ");

  for(i=0;i<n;i++)

    scanf("%d",&a[i]);

  printf("\nBefore Sorting:\n");

    for(i=0;i<n;i++)

    printf(" %d ",a[i]);

quicksort(a,0,n-1);

  printf("\nSorted elements:\n ");

  for(i=0;i<n;i++)

    printf(" %d ",a[i]);

  printf("\n");

}

void quicksort(int a[50],int left,int right)

{    int pivot,j,temp,i;

     if(left<right)

 {      pivot=left;

         i=left;

         j=right;

         while(i<j)

            {

             while(a[i]<=a[pivot]&&i<right)

                 i++;

             while(a[j]>a[pivot])

                 j--;

             if(i<j)

            {   temp=a[i];

                 a[i]=a[j];

                 a[j]=temp;

             }

         }

         temp=a[pivot];

         a[pivot]=a[j];

         a[j]=temp;

         quicksort(a,left,j-1);

         quicksort(a,j+1,right);

    }

}

Insertion, selection, and bubble sort

The following is a program for selection, insertion and bubble sort. If you have any doubts please let me know.

#include<stdio.h>

void basd(int[],int);

void insasd(int[],int);

void selasd(int[],int);

int i,j,k,temp;

main()

{

  int ch,a[100],i,j,n;

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

 scanf("%d",&n);

 printf("Enter the array elements:");

 for(i=0;i<n;i++)

 {

  scanf("%d",&a[i]);

 }

 do

 {

  printf("\nMenu:\n1.bubble\n2.selection\n3.insertion\n4.Exit\n");

  printf("Enter your choice:");

  scanf("%d",&ch);

  switch(ch)

  {

   case 1:

        basd(a,n);

        break;

   case 2:

        selasd(a,n);

        break;

   case 3:

        insasd(a,n);

        break;

    case 4:break;

    default:printf("Wrong choice!");

          break;

  }

}while(ch!=4);

}

void selasd(int b[],int n)

{

 int i,j,temp,a[50],k;

  printf("\nSELECTION SORT\n");

  printf("Unsorted array:\n");

 for(i=0;i<n;i++)

 printf("%d ",b[i]);

 printf("\n");

 for(i=0;i<n;i++)

  a[i]=b[i];

  for(i=0;i<n;i++)

  {

   for(j=i+1;j<n;j++)

   {

     if(a[j]<a[i])

     {

       temp=a[j];

       a[j]=a[i];

       a[i]=temp;

     }

   }

  }

  printf("\nAfter Selection Sort:");

  for(i=0;i<n;i++)

   printf(" %d",a[i]);

}

void insasd(int b[],int n)

{

  int a[50];

 printf("\nINSERTION SORT\n");

  printf("Unsorted array:\n");

 for(i=0;i<n;i++)

 printf("%d ",b[i]);

 printf("\n");

  for(i=0;i<n;i++)

  a[i]=b[i];

 for(i=1;i<n;i++)

 {

  temp=a[i];

  j=i-1;

  while(temp<a[j])

  {

   a[j+1]=a[j];

   j=j-1;

  }

  a[j+1]=temp;

  printf("\n");

 }

 printf("\nSorted array is:");

 for(i=0;i<n;i++)

 {

  printf(" %d ",a[i]);

 }

}

void basd(int b[],int n)

{

 int i,j,temp,a[50],k;

 printf("\nBUBBLE SORT\n");

  printf("Unsorted array:\n");

 for(i=0;i<n;i++)

 printf("%d ",b[i]);

 printf("\n");

  for(i=0;i<n;i++)

  a[i]=b[i];

 for(i=0;i<n;i++)

 {

  for(j=0;j<(n-i)-1;j++)

  {

    if(a[j]>a[j+1])

    {

     temp=a[j];

     a[j]=a[j+1];

     a[j+1]=temp;

    }

  }

 }

 printf("\nAfter Bubble Sort");

  for(i=0;i<n;i++)

   printf(" %d",a[i]);

   printf("\n");

}

Insertion, deletion and reversal of link list

This is a program to implement the various functions of a link list. If you have any doubts please let me know.
#include<stdio.h>
#include<stdlib.h>
struct node
{
 int data;
 struct node *next;
};
struct node *newn,*start=NULL,*ptr=NULL,*prev=NULL,*rev,*temp=NULL;
void insbeg();
void insend();
void inspos();
void insaft();
void delbeg();
void delend();
void delelement();
void display();
main()
{
 int ch1,ch,ch2;
 do
 {
  printf("\nMenu:\n1.Insertion\n2.Deletion\n3.Reversal\n4.Display\n5.Exit\n");
  printf("Enter your choice:");
  scanf("%d",&ch);
  switch(ch)
  {
   case 1:
    do
    {
     printf("\nSubmenu\n1.Insertion at beginning\n2.Insetion at End\n3.Insert at a specified position\n4.Insert after a specified node\n5.Exit from menu\n");

     printf("Enter your choice:");
     scanf("%d",&ch1);
     switch(ch1)
     {
      case 1:insbeg();
             break;
      case 2:
             insend();
             break;
      case 3:
             inspos();
             break;
      case 4:
             insaft();
             break;
      case 5:
             break;
      default:printf("Wrong choice\n");
              break;
     }
    }while(ch1!=5);
    break;
   case 2:
    do
    {
     printf("\nSubmenu\n1.Deletion at beginning\n2.Deletion at end\n3.Deletion of specific node\n4.Exit from this menu\n");
     printf("Enter your choice:");
     scanf("%d",&ch2);

     switch(ch2)
     {
      case 1:delbeg();
             break;
      case 2:delend();
             break;
      case 3:delelement();
             break;
      case 4:
             break;
      default:printf("Wrong choice\n");
              break;
     }
    }while(ch2!=4);
    break;
  case 3:
    if(start==NULL)
    {
     printf("\nUnderflow\n");
    }
    else
    {
     ptr=start;
     prev=NULL;
     while(ptr->next!=NULL)
     {
      rev=prev;
      prev=ptr;
      ptr=ptr->next;
      prev->next=rev;
     }
     start=prev;
     display();
   }
   break;
  case 4:
     display();
    break;
  case 5:
         break;
  default:printf("\nWrong Choice\n");
          break;
   }
  }while(ch!=5);
}

void insbeg()
{
 int num;
 printf("Enter the element:");
 scanf("%d",&num);
 newn=(struct node *)malloc(sizeof(struct node));
 if(start==NULL)
 {
  newn->data=num;
  newn->next=NULL;
  start=newn;
 }
 else
 {
  newn->data=num;
  newn->next=start;
  start=newn;
 }
}

void insend()
{
 int num;
 printf("Enter the element:");
 scanf("%d",&num);
 newn=(struct node *)malloc(sizeof(struct node));
  if(start==NULL)
 {
  newn->data=num;
  newn->next=NULL;
  start=newn;
 }
 else
 {
  ptr=start;
  while((ptr->next)!=NULL)
    ptr=ptr->next;
  newn->data=num;
  ptr->next=newn;
  newn->next=NULL;
 }
}

void inspos()
{
 int num,k=0,n;
 ptr=start;
 printf("Enter the the position at which the element must be inserted:");
 scanf("%d",&n);
 if(n==1)
 {
  insbeg();
 }
 else
 {
   printf("Enter the element:");
   scanf("%d",&num);
   while(k!=(n-1))
  {
    prev=ptr;
    ptr=ptr->next;
    k++;
   }
  newn=(struct node *)malloc(sizeof(struct node));
  newn->data=num;
  newn->next=ptr;
  prev->next=newn;
 }
}

void insaft()
{
 int n,num,c=0;
 ptr=start;
 printf("Enter the element:");
 scanf("%d",&num);
 printf("Enter the element after which insertion must be done:");
 scanf("%d",&n);
 while(ptr!=NULL)
 {
         if(ptr->data!=n)
         {
        ptr=ptr->next;
         }
         else
         {
                 c++;
                 {

                        newn=(struct node *)malloc(sizeof(struct node));
                        newn->data=num;
                        newn->next=ptr->next;
                        ptr->next=newn;
                        ptr=ptr->next;
                        break;
                }
         }
 }
 if(c==0)
         printf("NODE NOT FOUND");

}



void delbeg()
{
        if(start==NULL)
        {
                printf("\nUnderflow\n");
        }
        else
        {
                ptr=start;
                start=start->next;
                free(ptr);
        }
}

void delend()
{
        if(start==NULL)
        {
                printf("\nUnderflow\n");
        }
        else if(start->next==NULL)
          delbeg();
        else
        {
         ptr=start;
         while(ptr->next!=NULL)
        {
                prev=ptr;
                ptr=ptr->next;
        }
        prev->next=NULL;
        free(ptr);
        }
}
void delelement()
{
 int num,c=0;
 if(start==NULL)
 {
  printf("\nUnderflow\n");
 }
 else
 {
 printf("Enter the element to be deleted:");
 scanf("%d",&num);
 ptr=start;
 while(ptr!=NULL)
 {
        if(start->data==num)
        {
                 c++;
                delbeg();
                ptr=start;
                break;

        }
        else if(ptr->data==num)
        {
                c++;
          temp=ptr;
          prev->next=temp->next;
          ptr=ptr->next;
          free(temp);
          break;

        }

                prev=ptr;
                ptr=ptr->next;

 }

if(c==0)
 {
         printf("NODE NOT FOUND");
 }
}
}
 void display()
{
   if(start==NULL)
    {
     printf("\nUnderflow\n");
    }
    else
        {
    ptr=start;
    while(ptr->next!=NULL)
    {
     printf("=>%d  ",ptr->data);
     ptr=ptr->next;
    }
    printf("=>%d  ",ptr->data);
    }
}

Insertion and deletion of elements in a queue

The following program is the insertion, deletion of elements in a queue. If you have any doubts please let me know.

#include<stdio.h>

#include<stdlib.h>

struct node

{

        int data;

        struct node *next;

}*newn,*f=NULL,*r=NULL,*temp=NULL;

void ins();

void del();

void display();

main()

{

   int ch;

   do

   {

       printf("\nMenu:\n1.Insert\n2.Delete\n3.Display\n4.Exit\n");

       printf("Enter your choice:");

       scanf("%d",&ch);

       switch(ch)

       {

          case 1:

                  ins();

                  break;

          case 2:

                  del();

                  break;

          case 3:

                  display();

                  break;

           case 4:

                   break;

           default:

                    printf("Wrong Choice!");

                    break;

       }

   }while(ch!=4);

}

void ins()

{

        int x;

        printf("Enter the value to be inserted:");

        scanf("%d",&x);

        newn=(struct node *)malloc(sizeof(struct node));

        newn->data=x;

        if((f==NULL)&&(r==NULL))

        {

                newn->next=NULL;

                f=newn;

                r=newn;

        }

        else

        {

                r->next=newn;

                newn->next=NULL;

                r=r->next;

        }

}

void del()

{

        if((f==NULL)&&(r==NULL))

                printf("\nQueue Underflow\n");

        else if(f==r)

       {

         temp=f;

         f=NULL;

         r=NULL;

         free(temp);

       }

        else

        {

                temp=f;

                f=f->next;

                free(temp);

        }

}

void display()

{

        if((f==NULL)&&(r==NULL))

                printf("\nQueue Underflow\n");

        else

        {

                temp=f;

                while(temp!=r)

                {

                        printf("=>%d  ",temp->data);

                        temp=temp->next;

                }

                printf("=>%d  ",r->data);

        }

}

Insertion, Deletion, Peep, Isempty of elements.

The following is a program for ins,del,peep, isempty of elements. If you have any doubts please let me know.

#include<stdio.h>

#include<stdlib.h>

struct node

{

   int data;

   struct node *next;

};

struct node *top=NULL,*newn,*ptr=NULL;

void ins();

void del();

void peep();

void display();

void isempty();

main()

{

   int ch;

   do

   {

      printf("\nMenu:\n1.Insert\n2.Delete\n3.Peep\n4.Display\n5.Is empty\n6.Exit\n");

      printf("Enter your choice:");

      scanf("%d",&ch);

      switch(ch)

     {

         case 1:

            ins();

            break;

         case 2:

            del();

            break;

         case 3:

            peep();

            break;

         case 4:

            display();

            break;

         case 5:

            isempty();

            break;

         case 6:

            break;

         default:

             printf("Wrong choice");

             break;

      }

   }while(ch!=6);

}

void ins()

{

  int num;

  printf("Enter the element to be inserted:");

  scanf("%d",&num);

  newn=(struct node *)malloc(sizeof(struct node));

  newn->data=num;

  if(top==NULL)

 {

  newn->next=NULL;

  top=newn;

 }

 else

 {

  newn->next=top;

  top=newn;

 }

}

void del()

{

 if(top==NULL)

  printf("\nUndeflow\n");

 else

  {

   ptr=top;

   top=top->next;

   free(ptr);

  }

}

void peep()

{

 if(top==NULL)

 {

  printf("\nUnderflow\n");

 }

 else

 {

 printf("top: %d ",top->data);

 }

}

void display()

{

 ptr=top;

 if(ptr==NULL)

 {

  printf("\nUnderflow\n");

 }

 else

 {

 while(ptr->next!=NULL)

 {

  printf("=>%d ",ptr->data);

  ptr=ptr->next;

 }

 printf(" =>%d ",ptr->data);

 }

}

void isempty()

{

 if(top==NULL)

 {

  printf("\nStack is empty\n");

 }

 else

 {

  printf("\nStack is not empty\n");

 }

}

Polynomial Addition

The following is a C program to implement polynomial addition. If you have any doubts please let me know.
#include<stdio.h>
#include<stdlib.h>
struct node
{
 int d;
 int coef;
 struct node *next;
}*newn,*n=NULL,*p=NULL,*q=NULL,*r=NULL,*start1=NULL,*start2=NULL,*start3=NULL,*ptr=NULL,*prev=NULL;
void display(struct node *,struct node *);
void display1();
main()
{
 int a,b,i;
 i=0;
 printf("\nEnter values for polynomial1:\n");
 do
  {
 printf("Enter the coeff of x^%d:",i);
      newn=(struct node *)malloc(sizeof(struct node));
      scanf("%d",&newn->coef);
      newn->d=i;
      newn->next=p;
      p=newn;
      i++;
 printf("\n Do you wish to add more elements in polynomial 1:");
      printf("\nPress 1 to continue");
    scanf("%d",&a);
  }while(a==1);
 start1=p;
 printf("POLYNOMIAL 1:");
 display(start1,p);
 i=0;
 printf("\n\nEnter values for polynomial2:\n");
 do
 {
  printf("Enter the coef of x^%d:",i);
  newn=(struct node *)malloc(sizeof(struct node));
  scanf("%d",&newn->coef);
  newn->d=i;
  newn->next=q;
  q=newn;
  i++;
  printf("\n Do you wish to add more elements in polynomial 2:");
  printf("\nPress 1 to continue");
  scanf("%d",&b);
 }while(b==1);
 start2=q;
 printf("POLYNOMIAL 2:");
 display(start2,q);
 printf("\n\nSUM:");
 p=start1;
 q=start2;
 while((p!=NULL)&&(q!=NULL))
 {
if(p->d==q->d)
{
newn=(struct node *)malloc(sizeof(struct node));
newn->next=r;
newn->coef=p->coef+q->coef;
newn->d=p->d;
p=p->next;
q=q->next;
r=newn;
}
else if(p->d>q->d)
{
newn=(struct node *)malloc(sizeof(struct node));
newn->next=r;
newn->coef=p->coef;
newn->d=p->d;
p=p->next;
r=newn;
}
else if(p->d<q->d)
{
newn=(struct node *)malloc(sizeof(struct node));
newn->next=r;
newn->coef=q->coef;
newn->d=q->d;
q=q->next;
r=newn;
}
 }
 if(p==NULL)
 {
while(q!=NULL)
{
newn=(struct node *)malloc(sizeof(struct node));
newn->next=r;
newn->coef=q->coef;
newn->d=q->d;
q=q->next;
r=newn;
}
 }
 else if(q==NULL)
 {
while(p!=NULL)
{
newn=(struct node *)malloc(sizeof(struct node));
newn->next=r;
newn->coef=p->coef;
newn->d=p->d;
p=p->next;
r=newn;
}
 }

 start3=r;
 display1();
}

void display(struct node *start,struct node *ptr)
{
 ptr=start;
 while(ptr!=NULL)
 {
   printf("%dx^%d",ptr->coef,ptr->d);
   if(ptr->next!=NULL)
  printf("+");
   ptr=ptr->next;
 }
}
void display1()
{
 r=start3;
 prev=NULL;
 while(r!=NULL)
 {
   ptr=prev;
   prev=r;
   r=r->next;
   prev->next=ptr;
 }
 start3=prev;
 r=start3;
 while(r!=NULL)
 {
   printf("%dx^%d",r->coef,r->d);
   if(r->next!=NULL)
  printf("+");
   r=r->next;
 }
}

Heap Sort

This is the implementation of heap sort using the C programming language. If you have any doubts, please let me know.

#include<stdio.h>

int tree[50],n=0;

void del();

void ins(int);

main()

{

            int x,i,a;

            printf("\nEnter the number of elements:");

            scanf("%d",&a);

            printf("\nEnter the elements:");

            for(i=0;i<a;i++)

            {

                        scanf("%d",&x);

                        ins(x);

            }

            printf("\nAfter Sorting:\n");

            del();   

}

void ins(int x)

{

            int ptr,par;

            n=n+1;

            ptr=n;

            while(ptr>1)

            {

                        par=ptr/2;

                        if(x<=tree[par])

                        {

                                    tree[ptr]=x;

                                    return;

                        }

                        tree[ptr]=tree[par];

                        ptr=par;

            }

            tree[1]=x;

            return;

}

void del()

{

            int i,x,ptr,last,left,right;

            while(n!=0)

            {

                        x=tree[1];

                        printf(" %d  ",x);

                        last=tree[n];

                        n=n-1;

                        ptr=1;

                        left=2;

                        right=3;

                        while(right<=n)

                        {

                                    if(last>=tree[left]&&last>=tree[right])

                                    {

                                                tree[ptr]=last;

                                                break;

                                    }

                                    else if(tree[right]<=tree[left])

                                    {

                                                tree[ptr]=tree[left];

                                                ptr=left;

                                    }

                                    else

                                    {

                                                tree[ptr]=tree[right];

                                                ptr=right;

                                    }

                                    left=2*ptr;

                                    right=left+1;

                        }

                        if((left==n)&&(last<tree[left]))

                        {

                                    tree[ptr]=tree[left];

                                    ptr=left;

                        }

                        tree[ptr]=last;

}

            return;

}