C Code for reversing linked list using head

//implementing linked list using head

//printing recursive

//printing reverse recursive

#include<stdio.h>

#include<malloc.h>

struct node

{

int data;

struct node *next;

};

void insert(struct node **,int );

//void display(struct node *head)

//void displayReverse(struct node *head);

int main()

{

printf("\n\n");

struct node *head=NULL;

insert(&head,10);

insert(&head,30);

insert(&head,19);

insert(&head,12);

insert(&head,99);

display(head);

printf("\n\n");

displayReverse(head);

printf("\n\n");

delete(&head);

printf("\n\n");

//display(head);

//printf("\n\n");

return 0;

}

void insert(struct node **head,int d)

{

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

newnode->data=d;

if(*head==NULL)

{

*head=newnode;

(*head)->next=NULL;

}

else

{

newnode->next=*head;

*head=newnode;

}

}

void display(struct node *head)

{

//printf("List in actual order is:\n");

printf("%d ",head->data);

if(head->next==NULL)

{

return;

}

else

{

display(head->next);

}

}

void displayReverse(struct node *head)

{

//printf("%d ",head->data);

if(head==NULL)

return;

else

displayReverse(head->next);

//printf("List in reversed order is:\n");

printf("%d ",head->data);

}

void delete(struct node **head)

{

struct node *temp;

while (*head != NULL)

{

temp = *head;

*head = (*head)->next;

free(temp);

}

}

/*

99 12 19 30 10

10 30 19 12 99 */

C code for inserting at middle, deleting at middle

/*Linked list first last middle insert without create function search and delete */

#include<stdio.h>

#include<malloc.h>

struct node

{

int data;

struct node *next;

};

struct node *first=NULL;

struct node *ptr=NULL;

struct node *prev=NULL;

struct node *last=NULL;

struct node *newnode=NULL;

int val,pos,count=0,i;

void insert_first();

void insert_last();

void insert_pos();

void display();

int main()

{

display();

insert_first();

insert_first();

insert_first();

display();

printf("\n");

insert_last();

insert_last();

insert_last();

display();

insert_pos();

insert_pos();

display();

printf("\n");

return 0;

}

void insert_first()

{

printf("enter a number to insert at first:\n");

scanf("%d",&val);

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

newnode->data=val;

newnode->next=NULL;

if(first==NULL)

{

first=newnode;

first->next=NULL;

}

else

{

newnode->next=first;

first=newnode;

}

}

void display()

{

if(first==NULL)

{

printf("No element to display.\n");

}

else

{

/*for(ptr=first;ptr!=NULL;ptr=ptr->next)

{

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

}*/

ptr=first;

while(ptr!=NULL)

{

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

ptr=ptr->next;

}

}

}

void insert_last()

{

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

printf("enter a number to insert at last:\n");

scanf("%d",&newnode->data);

newnode->next=NULL;

if(first==NULL)

{

first=newnode;

}

else

{

ptr=first;

while(ptr->next!=NULL)//ptr-next is must as segflt

{

ptr=ptr->next;

}

ptr->next=newnode;

newnode->next=NULL;

}

}

void insert_pos()

{

int pos, val, cnt = 0, i;

printf("\nEnter the position:\n ");

scanf("%d", &pos);

printf("\nEnter the value for the Node:\n");

scanf("%d", &val);

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

newnode->data=val;

ptr = first;

while (ptr != NULL)

{

ptr = ptr->next;

cnt++;

}

if (pos == 1)

{

if (first == last && first == NULL)

{

first = last = newnode;

first->next = NULL;

last->next = NULL;

}

else

{

newnode->next=first;

first=newnode;

}

printf("\nInserted\n");

}

else if (pos>1 && pos<=cnt)

{

ptr = first;

for (i = 1;i < pos;i++)

{

prev = ptr;

ptr = ptr->next;

}

prev->next = newnode;

newnode->next = ptr;

printf("\nData inserted.\n");

}

else

{

printf("\nPosition is out of range\n");

}

}

/*

No element to display.

enter a number to insert at first:

1

enter a number to insert at first:

2

enter a number to insert at first:

3

3 2 1

enter a number to insert at last:

4

enter a number to insert at last:

5

enter a number to insert at last:

6

3 2 1 4 5 6

Enter the position:

2

Enter the value for the Node:

22

Data inserted.

Enter the position:

1

Enter the value for the Node:

11

Inserted

11 3 22 2 1 4 5 6

*/

C code for implementing tree operations traverse

tree implementation in c

#include<stdio.h>

#include<malloc.h>

void insert(int);

void traverse();

struct node

{

int data;

struct node *left;

struct node *right;

};

struct node *root;

int main()

{

root=NULL;

insert('B');

insert(10);

insert(5);

insert(15);

insert(12);

insert(2);

traverse();

return 0;

}

void insert(int d)

{

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

newnode->data=d;

newnode->left=NULL;

newnode->right=NULL;

struct node *ptr=root;

if(root==NULL)

{

root=newnode;

//newnode->left=NULL;

//newnode->right=NULL;

}

else

{

while(ptr!=NULL)

{

if(d<ptr->data)

{

if(ptr->left==NULL)

{

ptr->left=newnode;

ptr=NULL;

}

else

{

ptr=ptr->left;

}

}

else

{

//if(d>ptr->data)

//{

if(ptr->right==NULL)

{

ptr->right=newnode;

ptr=NULL;

}

else

{

ptr=ptr->right;

}

}

}

}//else first ends

}//insert ends

void inorder(struct node *ptr);

void preorder(struct node *ptr);

void postorder(struct node *ptr);

void traverse()

{

printf("\nInorder\n");

inorder(root);

printf("\nPre order\n");

preorder(root);

printf("\nPost Order\n");

postorder(root);

printf("\n\n");

}//traverse ends here

void inorder(struct node *ptr)

{

if(ptr!=NULL)

{

inorder(ptr->left);

printf("%d ",ptr->data);

inorder(ptr->right);

}

}

void preorder(struct node *ptr)

{

if(ptr!=NULL)

{

printf("%d ",ptr->data);

preorder(ptr->left);

preorder(ptr->right);

}

}

void postorder(struct node *ptr)

{

if(ptr!=NULL)

{

postorder(ptr->left);

postorder(ptr->right);

printf("%d ",ptr->data);

}

}

/*

Inorder

2 5 10 12 15 66

Pre order

66 10 5 2 15 12

Post Order

2 5 12 15 10 66

*/

C code for Linked List Operations at beginning

linked list implementation in C

//insert at beginning,delete at beginning

//display, reverse

#include<stdio.h>

#include<malloc.h>

void insert(int d);

void display();

void deletee();

void reverse();

struct node

{

int data;

struct node *next;

};

struct node *start;

int main()

{

printf("\n\n");

start=NULL;//starting with empty list

insert(10);

insert(10);

insert(15);

insert(10);

insert(11);

insert(15);

insert(99);

printf("\ndisplay() called:\n");

display();

printf("\ndeletee() called:\n");

deletee();

display();

printf("\nreverse() called:\n");

reverse();

display();

printf("\n\n");

return 0;

}

void insert(int d)

{

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

newnode->data=d;

newnode->next=start;

start=newnode;

}

void display()

{

struct node *ptr=start;

while(ptr!=NULL)

{

printf("%d ",ptr->data);

ptr=ptr->next;

}

}

void deletee()

{

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

temp=start;

start=start->next;

if(temp!=NULL)

{

free(temp);

}

}

void reverse()

{

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

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

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

next=NULL;

result=NULL;

current=start;

while(current!=NULL)

{

next=current->next;

current->next=result;

result=current;

current=next;

}

start=result;

}

/*

display() called:

99 15 11 10 15 10 10

deletee() called:

15 11 10 15 10 10

reverse() called:

10 10 15 10 11 15

*/

C code for deleting duplicate words in a sentence

C Program to delete all duplicate words in a sentence
//C code for removing repeated words of among multiple strings
#include <stdio.h>
#include <string.h>
void main()
{
    char a[100], b[20][20];
    int i, j = 0, k = 0, n, m;
    printf("enter a string\n");
    scanf("%[^\n]s", a);
    for (i = 0;a[i] != '\0';i++)
    {
        if (a[i] == ' ')
        {
            b[k][j] = '\0';
            k++;
            j = 0;
        }
        else
        {
            b[k][j] = a[i];
            j++;
        }
    }
    b[k][j] = '\0';
    for (i = 0;i <= k;i++)
    {
        for (j = i + 1;j <= k;j++)
        {
            if (strcmp(b[i], b[j]) == 0)
            {
                for (m = j;m <= k;m++)
                    strcpy(b[m], b[m + 1]);
                k--;
            }
        }
    }
 for (n = 0;n <= k;n++)
    {
        printf("%s ", b[n]);
    }
}
/*
enter a string:
india is great is countrin in india asia great
india is great countrin in asia

*/

C Code for deleting repeated characters in a sentence

C Program to delete duplicate characters in a string/sentence
//C code for removing repeated characters of a string/sentence
#include<stdio.h>
#include<string.h>
int main()
{
char a[200];
int i,j,k,n;

printf("Enter a few chars and strings:\n");
gets(a);
printf("\nEntered string is :%s \n",a);

printf("\nUpdated string without repeated characters is\n");
n=strlen(a);
for(i=0;i<n;i++)
{
   for(j=i+1;j<n;)//mind it no icrement
   {
      if(a[j]==a[i])
      {
         for(k=j;k<n;k++)
{
             a[k]=a[k+1];
}
          n--;//else array will contain 0 in deleted duplicate value
      }
      else
         j++;
   }
}

for(i=0;i<n;i++)
    printf("%c",a[i]);
printf("\n");
}
/*
Enter a few chars and strings:
india is great aa bb cc dd ee ff gg hh ii jj kk

Entered string is :india is great aa bb cc dd ee ff gg hh ii jj kk

Updated string without repeated characters is

inda sgretbcfhjk
*/

C code for deleting duplicate elements in an array

C Program to delete duplicate elements in an array
//C code for removing repeated values of an array

#include<stdio.h>
int main()
{
int a[20],i,j,k,n;

printf("\nnEnter array size : ");
scanf("%d",&n);

printf("\nnAccept Numbers : ",n);
for(i=0;i<n;i++)
scanf("%d",&a[i]);


printf("\nnOriginal array is : ");
for(i=0;i<n;i++)
printf(" %d",a[i]);

printf("\nnUpdated array is  : ");
for(i=0;i<n;i++)
{
   for(j=i+1;j<n;)
   {
      if(a[j]==a[i])
      {
         for(k=j;k<n;k++)
{
             a[k]=a[k+1];
}
          n--;//else array will contain 0 in deleted duplicate value
      }
      else
         j++;
   }
}

for(i=0;i<n;i++)
    printf("%d \t",a[i]);
printf("\n");
}
/*
array size : 5
Numbers : 22
33
44
44
22
array is :  22 33 44 44 22
array is  : 22         33      44

*/