History Of C

In the beginning was Charles Babbage and his Analytical Engine, a machine
he built in 1822 that could be programmed to carry out different computations.
Move forward more than 100 years, where the U.S. government in
1942 used concepts from Babbage’s engine to create the ENIAC, the first
modern computer.
Meanwhile, over at the AT&T Bell Labs, in 1972 Dennis Ritchie was working
with two languages: B (for Bell) and BCPL (Basic Combined Programming
Language). Inspired by Pascal, Mr. Ritchie developed the C programming
language.

Linked List implementation

#include"m_list.h"

void main()
{
list *first=NULL,*second=NULL,*third=NULL;
int choice,i;
char ch='y';
while(1)
{
clrscr();
printf("
case 1: Create list");
printf("
case 2: Add in the list");
printf("
case 3: Delete in the list");
printf("
case 4: Append two list");
printf("
case 5: show list");
printf("
case 6: Exit");
printf("
Enter your choice : ");
scanf("%d",&choice);
switch(choice)
{
case 1: //create list
while(ch!='n')
{
printf("Enter element : ");
scanf("%d",&i);
create(&first,i);
printf("Enter element (y/n) : ");
fflush(stdin);
scanf("%c",&ch);
}
break;
case 2: //add in the list
int c;
clrscr();
printf("case 1: Add in Beginning");
printf("case 2: Add in End");
printf("case 3: Add After a given element");
printf("case 4: Return to main menu");
printf("Enter your choice : ");
scanf("%d",&c);
switch(c)
{
case 1: add_at_beg(&first);
break;
case 2: add_at_end(&first);
break;
case 3: add_after_given_element(&first);
break;
case 4: break;
}
break;
case 3:
clrscr();
printf("case 1: Delete in Beginning");
printf("case 2: Delete in End");
printf("case 3: Delete a specified element");
printf("case 4: Return to main menu");
printf("Enter your choice : ");
scanf("%d",&c);
switch(c)
{
case 1: del_at_beg(&first);
break;
case 2: del_at_end(&first);
break;
case 3: del_specified_element(&first);
break;
case 4: break;
}
break;
case 4:
char ch='y';
printf("Enter element in second list : ");
while(ch!='n')
{
printf("Enter element : ");
scanf("%d",&i);
create(&second,i);
printf("Enter element (y/n) : ");
fflush(stdin);
scanf("%c",&ch);
}
append(&third,first,second);

break;
case 5: //show list
clrscr();
printf("
case 1: List 1");
printf("
case 2: List 2");
printf("
case 3: List 3");
printf("
Enter choice : ");
scanf("%d",&choice);
switch(choice)
{
case 1: show(first);break;
case 2: show(second);break;
case 3: show(third);break;
}
break;
case 6: exit(0);

}


}
}


*********************************
#include
#include
#include
#include
typedef struct list
{
int info;
struct list *next;
};

//.................Function Declaration ...........

void create(struct list **p,int i)
{
struct list *temp,*q=*p;
temp=(struct list*)malloc(sizeof(struct list));
temp->info=i;
temp->next=NULL;
if(*p==NULL)
*p=temp;
else
{
while(q->next!=NULL)
q=q->next;
q->next=temp;
}
}
int append(struct list **t,struct list *f,struct list *s)
{
struct list *temp=*t;
if(f==NULL && s==NULL)
return 0;
while(f)
{
create(t,f->info);
f=f->next;
}
while(s)
{
create(t,s->info);
s=s->next;
}

return 0;
}
void show(struct list *p)
{
if(p==NULL)
printf(" List is Empty");
else
while(p)
{
printf("%d ",p->info);
p=p->next;
}
getch();
}
void add_at_beg(struct list **l)
{
struct list *temp=(struct list *)malloc(sizeof(struct list));
printf("
Enter element : ");
scanf("%d",&temp->info);
temp->next=NULL;
if(*l==NULL)
*l=temp;
else
{
temp->next=*l;
*l=temp;
}
}
void del_at_beg(struct list **l)
{
list *temp;
if(*l==NULL)
{
printf("
List is empty");
getch();
}
else
{
temp=*l;
*l=(*l)->next;
free(temp);
}
}
void add_at_end(struct list **l)
{
list *temp,*p;
temp=(struct list *)malloc(sizeof(struct list));
printf("
Enter element : ");
scanf("%d",&temp->info);
temp->next=NULL;
if(*l==NULL)
*l=temp;
else
{
p=*l;
while(p->next!=NULL)
p=p->next;
p->next=temp;
}
}

void del_at_end(struct list **l)
{
list *temp,*p;
if(*l==NULL)
{
printf("
List is Empty");
getch();
}
else if((*l)->next==NULL)
{
temp=*l;
*l=NULL;
free(temp);
}
else
{
p=*l;
while(p->next->next!=NULL)
p=p->next;
temp=p->next->next;
p->next=NULL;
free(temp);
}
}
void add_after_given_element(list **l)
{
list *temp,*p;
int m;
temp=(struct list *)malloc(sizeof(struct list));
printf("
Enter element : ");
scanf("%d",&temp->info);
printf("
Enter position after which element inserted : ");
scanf("%d",&m);
temp->next=NULL;
if(*l==NULL)
*l=temp;
else
{
p=*l;
while(p->next!=NULL)
if(p->info==m)
break;
else
p=p->next;

temp->next=p->next;
p->next=temp;

}
}
void del_specified_element(list **l)
{
list *temp,*p,*q;
int m;
printf("
Enter element which is deleted : ");
scanf("%d",&m);
if(*l==NULL)
{
printf("
List is Empty");
getch();
}
else if((*l)->next!=NULL && (*l)->info==m)
{
temp=*l;
*l=(*l)->next;
free(temp);
}
else if((*l)->next==NULL && (*l)->info==m)
{
temp=*l;
*l=NULL;
free(temp);
}
else
{
p=*l;
while(p!=NULL)
if(p->info==m)
break;
else
{
q=p;
p=p->next;
}
temp=p;
q->next=p->next;
free(temp);
}
}

Program for finding the transpose of a martix in sparse form

#include <stdio.h>
#include <conio.h>
int a[100][100],b[100][100];

void main()
{
int i,m,n,p,q,col,t;
clrscr();
printf("Enter the no. of rows");
scanf("%d", &a[0][0]);
printf("Enter the no. of cols");
scanf("%d", &a[0][1]);
printf("Enter the number of non zero terms");
scanf("%d", &a[0][2]);

for(i=1;i<=a[0][2];i++)
{
printf("Enter the value (that is non zero)");
scanf("%d",&a[i][2]);
printf("Enter the row for %d : ",a[i][2]);
scanf("%d",&a[i][0]);
printf("Enter the col for %d : ",a[i][2]);
scanf("%d",&a[i][1]);
}

/* Printing for testing the sparse input */
printf("
*****************************
The martix you entered is
************************

Row Col Value ");
for ( i = 0;i <= a[0][2];i++)
{
printf("%d %d %d " , a[i][0],a[i][1],a[i][2]);
}

/* Calling function for evaluation of transpose */

m = a[0][0];
n = a[0][1];
t = a[0][2];

b[0][0] = n;
b[0][1] = m;
b[0][2] = t;

q=1;

for( col = 1; col <=n; col++)
{
for(p = 1; p<=t;p++)
{
if(a[p][1] == col)
{
b[q][0] = a[p][1];
b[q][1] =a[p][0];
b[q][2] = a[p][2];
q++;
}
}
} //end of outer for loop

/* Printing the transposed matrix */

getch();
printf("
The Transpose of the above matrix is ");
for ( i = 0;i <= a[0][2];i++)
{
printf("%d %d %d " , b[i][0],b[i][1],b[i][2]);
}
getch();
}

XOR list example

#include <stdio.h>
#include <conio.h>
#include

struct xnode
{
int data;
unsigned long direction;
};

struct xnode *add_data(int data, struct xnode* list);
void walk_list(struct xnode *list);

int main(void)
{

struct xnode *l2 = add_data(2, NULL);
struct xnode *l1 = add_data(1, l2);
struct xnode *l3 = add_data(3, l2);
struct xnode *l4 = add_data(4, l3);

printf("front -> back....\n");
walk_list(l1);
printf("back -> front....\n");
walk_list(l4);

return 0;
}

struct xnode *add_data(int data, struct xnode *list)
{
struct xnode *newxnode = malloc(sizeof(struct xnode));

assert(newxnode);
newxnode->direction = (unsigned long)list;
newxnode->data = data;

if(list != NULL)
list->direction ^= (unsigned long)newxnode;

return newxnode;
}

void walk_list(struct xnode *list)
{
unsigned long prev = 0;

while(list != NULL) {
unsigned long next = prev ^ list->direction;
printf("%d ", list->data);
prev = (unsigned long)list;
list = (struct xnode *)next;
}

printf("\n");
}

Program for demonstration of Tree Operations - INSERTION, INORDER .

#include <stdio.h>
#include <conio.h>
# include

struct node
{
struct node *left;
int data;
struct node *right;
};

void main()
{
void insert(struct node **,int);
void inorder(struct node *);
void postorder(struct node *);
void preorder(struct node *);
struct node *ptr;
int will,i,num;
ptr = NULL;
ptr->data=NULL;
clrscr();

printf("Enter the number of terms you want to add to the tree.");
scanf("%d",&will);

/* Getting Input */
for(i=0;i
{
printf("Enter the item");
scanf("%d",&num);
insert(&ptr,num);
}

getch();
printf("INORDER TRAVERSAL");
inorder(ptr);
getch();
printf("PREORDER TRAVERSAL");
preorder(ptr);
getch();
printf("POSTORDER TRAVERSAL");
postorder(ptr);
getch();
}



void insert(struct node **p,int num)
{


if((*p)==NULL)
{ printf("Leaf node created.");
(*p)=malloc(sizeof(struct node));
(*p)->left = NULL;
(*p)->right = NULL;
(*p)->data = num;
return;
}
else
{ if(num==(*p)->data)
{
printf("REPEATED ENTRY ERROR
VALUE REJECTED");
return;
}
if(num<(*p)->data)
{
printf("
Directed to left link.");
insert(&((*p)->left),num);
}
else
{
printf("Directed to right link.");
insert(&((*p)->right),num);
}
}
return;
}


void inorder(struct node *p)
{
if(p!=NULL)
{
inorder(p->left);
printf("Data :%d",p->data);
inorder(p->right);
}
else
return;
}


void preorder(struct node *p)
{
if(p!=NULL)
{
printf("Data :%d",p->data);
preorder(p->left);
preorder(p->right);
}
else
return;
}


void postorder(struct node *p)
{
if(p!=NULL)
{
postorder(p->left);
postorder(p->right);
printf("
Data :%d",p->data);
}
else
return;
}

Search An Element in Linked List

#include stdio.h>
#include conio.h>
#include malloc.h>
struct linlst
{
int info;
struct link *next;
}
start, *node;

int search(int);
void main()
{
int no,i,item,pos;
clrscr();
start.next=NULL;
node=&start;
printf("How many nodes, you want in linked list? ");
scanf("%d",&no);
printf(" ");
for(i=0;i
{
node->next=(struct linlst *)malloc(sizeof(struct linlst));
printf("Enter element in node %d: ",i+1);
scanf("%d",&node->info);
node=node->next;
}
node->next=NULL;
printf("Linked list(only with info field) is:");

node=&start;
while(node->next!=NULL)
{
printf("%d ",node->info);
node=node->next;
}
printf("Enter item to be searched : ");
scanf("%d",&item);
pos=search(item);
if(pos<=no)
printf("Your item is at node %d",pos);
else
printf("Sorry! item is no in linked list.a");
getch();
}

int search(int item)
{
int n=1;
node=&start;
while(node->next!=NULL)
{
if(node->info==item)
break;
else
n++;
node=node->next;
}
return n;
}

Program for demonstration of Tree Operations - INSERTION, INORDER .

# include
# include
# include

struct node
{
struct node *left;
int data;
struct node *right;
};

void main()
{
void insert(struct node **,int);
void inorder(struct node *);
void postorder(struct node *);
void preorder(struct node *);
struct node *ptr;
int will,i,num;
ptr = NULL;
ptr->data=NULL;
clrscr();

printf("Enter the number of terms you want to add to the tree.");
scanf("%d",&will);

/* Getting Input */
for(i=0;i
{
printf("Enter the item");
scanf("%d",&num);
insert(&ptr,num);
}

getch();
printf("INORDER TRAVERSAL");
inorder(ptr);
getch();
printf("PREORDER TRAVERSAL");
preorder(ptr);
getch();
printf("POSTORDER TRAVERSAL");
postorder(ptr);
getch();
}



void insert(struct node **p,int num)
{


if((*p)==NULL)
{ printf("Leaf node created.");
(*p)=malloc(sizeof(struct node));
(*p)->left = NULL;
(*p)->right = NULL;
(*p)->data = num;
return;
}
else
{ if(num==(*p)->data)
{
printf("REPEATED ENTRY ERROR
VALUE REJECTED");
return;
}
if(num<(*p)->data)
{
printf("
Directed to left link.");
insert(&((*p)->left),num);
}
else
{
printf("Directed to right link.");
insert(&((*p)->right),num);
}
}
return;
}


void inorder(struct node *p)
{
if(p!=NULL)
{
inorder(p->left);
printf("Data :%d",p->data);
inorder(p->right);
}
else
return;
}


void preorder(struct node *p)
{
if(p!=NULL)
{
printf("Data :%d",p->data);
preorder(p->left);
preorder(p->right);
}
else
return;
}


void postorder(struct node *p)
{
if(p!=NULL)
{
postorder(p->left);
postorder(p->right);
printf("
Data :%d",p->data);
}
else
return;
}