Queue using Linklist

#include<stdio.h>
#include<conio.h>
struct Node
{
int num;
struct Node*next;


};
struct Node*start=NULL;
void addToQueue(int num)
{
struct Node *t,*j;
t=(struct Node*)malloc(sizeof(struct Node));
t->num=num;
t->next=NULL;
if(start==NULL)
{
start=t;
}
else
{
j=start;
while(j->next!=NULL)
{
j=j->next;
}
j->next=t;
}
}
int removeFromQueue()
{
struct Node *t;
int num;
if(start==NULL)return 0;//queue is empty
num=start->num;
t=start;
start=start->next;
free(t);
return num;


}
int isQueueEmpty()
{
return start==NULL;


}
void main()
{
int ch,num;
while(1)
{
printf("1 Add to queue\n");
printf("2 Remove from queue\n");
printf("3 Enter your choice");
scanf("%d",&ch);
if(ch==1)
{
printf("Enter number to add to queue ");
scanf("%d",&num);
addToQueue(num);
printf("%d added to queue\n",num);
}
if(ch==2)
{
if(isQueueEmpty())
{
printf("Queue is empty\n");
}
else
{
num=removeFromQueue();
printf("%d removed from queue\n",num);
}
}
if(ch==3)
{
break;
}
}
}

Circular Queue implementation

 Circular Queue implementation using C programming.


#include<stdio.h>
int queue[10];
int lowerBound=0;
int upperBound=9;
int front=-1;
int rear=-1;
int size=0;

void addToQueue(int num)                   
{
if(size==(upperBound-lowerBound)+1) return; // queue Full
if(rear<upperBound)
{
rear++;
}
else
{
rear=lowerBound;
}


queue[rear]=num;
size++;
if(front==-1)front=0;
}


int removeFromQueue()
{
int num;
if(size==0)return 0; //queue Empty
num=queue[front];
if(front<upperBound)
{
front++;
}
else
{
front=lowerBound;
}
size--;
return num;


}
int isQueueFull()
{
return size==(upperBound-lowerBound)+1;
}


int isQueueEmpty()
{
return size==0;
}


void main()
{
int ch,num;
while(1)
{
printf("1. Add To Queue\n");
printf("2. Remove From Queue\n");
printf("3. Enter your choice");
scanf("%d",&ch);
if(ch==1)
{
if(isQueueFull())
{
printf("Queue is full\n");
}
else
{
printf("Enter number to add to queue");
scanf("%d",&num);
if(num==0)
{
printf("Cannot add zero to queue\n");
}
else
{
addToQueue(num);
printf("%d added to queue \n",num);
}
}
}
if(ch==2)
{
if(isQueueEmpty())
{
printf("Queue is empty\n");
}
else
{
num=removeFromQueue();
printf("%d removed from queue\n",num);
}
}
if(ch==3)
{
break;
}
}
}

An example of queue using Array

An example of queue using Array

#include<stdio.h>
int queue[10];
int lowerBound=0;
int upperBound=9;
int front=-1;
int rear=-1;
void addToQueue(int num)
{
if(rear==upperBound) return; // queue Full
rear++;
queue[rear]=num;
if(front==-1)front=0;
}
int removeFromQueue()
{
int num,i;
if(rear==-1)return 0; //queue Empty
num=queue[front];
i=0;
while(i<rear)
{
queue[i]=queue[i+1];
i++;
}
rear--;
if(rear==-1)front=-1;
return num;
}

int isQueueFull()
{
return rear==upperBound;
}

int isQueueEmpty()
{
return rear==-1;
}

void main()
{
int ch,num;
while(1)
{
printf("1. Add To Queue\n");
printf("2. Remove From Queue\n");
printf("3. Enter your choice");
scanf("%d",&ch);
if(ch==1)
{
if(isQueueFull())
{
printf("Queue is full\n");
}
else
{
printf("Enter number to add to queue");
scanf("%d",&num);
if(num==0)
{
printf("Cannot add zero to queue\n");
}
else
{
addToQueue(num);
printf("%d added to queue \n",num);
}
}
}
if(ch==2)
{
if(isQueueEmpty())
{
printf("Queue is empty\n");
}
else
{
num=removeFromQueue();
printf("%d removed from queue\n",num);
}
}
if(ch==3)
{
break;
}
}
}
-----------------------------------------------------------------------------------------------------

Doubly Linked list

Doubly Linked list......................Using C programming.

struct Node

{

int num;

struct Node *next;

struct Node *prev;

};

struct Node *start=NULL;

struct Node *end=NULL;

void addAtEnd(int num)

{

struct Node *t;

t=(struct Node *)malloc(sizeof(struct Node));

t->num=num;

t->next=NULL;

t->prev=NULL ;

if(start==NULL)

{

start=t;

end=t;

}

else

{

end->next=t;

t->prev=end;

end=t;

}

}

void insertAtTop(int num)

{

struct Node *t;

t=(struct Node*)malloc(sizeof(struct Node));

t->num=num;

t->next=NULL;

t->prev=NULL;

if(start==NULL)

{

start=t;

end=t;

}

else

{

t->next=start;

start->next=t;

start=t;

}

}

void insertAtPosition(int num,int pos)

{

struct Node *p1;

int x;

struct Node *t;

t=(struct Node *)malloc(sizeof(struct Node));

t->num=num;

t->next=NULL;

t->prev=NULL;

x=1;

p1=start;

while(x

{

p1=p1->next;

x++;

}

if(p1==NULL)

{

if(p1==start)

{

start=t;

end=t;

}

else

{

end->next=t;

t->prev=end;

end=t;

}

}

else

{

if(p1==start)

{

t->next=start;

start->prev=t;

start=t;

}

else

{

t->next=p1;

t->prev=p1->next;

p1->prev->next=t;

p1->prev=t;

}

}

}

void removeFromPosition(int pos)

{

struct Node *p1;

int x;

if(start==NULL)

{

printf("Invalid Position\n");

return;

}

x=1;

p1=start;

while(x

{

p1=p1->next;

x++;

}

if(p1==NULL)

{

printf("Invalid Position\n");

return;

}

if(p1==start && p1==end)

{

start=NULL;

end=NULL;

}

else

{

if(p1==start)

{

start=start->next;

start->prev=NULL;

}

else

{

if(p1==end)

{

end=end->prev;

end->next=NULL;

}

else

{

p1->prev->next=p1->next;

p1->next->prev=p1->prev;

}

}

}

free(p1);

}

void traverseTopToBottom()

{

struct Node *t;

t=start;

while(t!=NULL)

{

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

t=t->next;

}

}

void traverseBottomToTop()

{

struct Node *t;

t=end;

while(t!=NULL)

{

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

t=t->prev;

}

}

void main()

{

int ch, num, pos;

while(1)

{

printf("1. Add a node at end\n");

printf("2. Insert a node at top\n");

printf("3. Insert a node at a position\n");

printf("4. Remove a node from a position \n");

printf("5. Traverse -Top To Bottom\n");

printf("6. Traverse - Bottom To Top\n");

printf("7. Exit\n");

printf("Enter your choice:");

scanf("%d",&ch);

if(ch==1)

{

printf("Enter a number to add at end:");

scanf("%d",&num);

addAtEnd(num);

}

if(ch==2)

{

printf("Enter a number to insert at top");

scanf("%d",&num);

insertAtTop(num);

}

if(ch==3)

{

printf("Enter a number to insert:");

scanf("%d",&num);

printf("Enter the position where you want to insert:");

scanf("%d",&pos);

insertAtPosition(num,pos);

}

if(ch==4)

{

printf("Enter positionj of the node to remove:");

scanf("%d",&pos);

removeFromPosition(pos);

}

if(ch==5)

{

traverseTopToBottom();

}

if(ch==6)

{

traverseBottomToTop();

}

if(ch==7)

{

break;

}

}

}

Singly Link List Implementation --- C code

Singly Link List Implementation through ~ C programming

struct Node

{

int num;

struct Node *next;

};

struct Node *start=NULL ;

void addAtEnd(int num)

{

struct Node *t,*j;

t=(struct Node *)malloc(sizeof(struct Node));

t->num=num;

t->next=NULL;

if(start==NULL)

{

start=t;

}

else

{

j=start;

while(j->next!=NULL)

{

j=j->next;

}

j->next=t;

}

}

void insertAtTop(int num)

{

struct Node *t;

t=(struct Node *)malloc(sizeof(struct Node));

t->num=num;

t->next=NULL;

if(start==NULL)

{

start=t;

}

else

{

t->next=start;

start=t;

}

}

void insertAtPosition(int num, int pos)

{

struct Node *p1,*p2;

int x;

struct Node *t;

t=(struct Node *)malloc(sizeof(struct Node));

t->num=num;

t->next=NULL;

x=1;

p1=start;

while(x

{

p2=p1;

p1=p1->next;

x++;

}

if(p1==NULL)

{

if(start==NULL)

{

start=t;

}

else

{

p2->next=t;

}

}

else

{

if(p1==start)

{

t->next=start;

start=t;

}

else

{

t->next=p1;

p2->next=t;

}

}

}

void removeFromPosition(int pos)

{

struct Node *p1,*p2;

int x;

if(start==NULL)

{

printf("Invalid Position");

return;

}

x=1;

p1=start;

while(x

{

p2=p1;

p1=p1->next;

x++;

}

if(p1==NULL)

{

printf("Invalid position\n");

return;

}

if(p1==start)

{

start=start->next;

}

else

{

p2->next=p1->next;

}

free(p1);

}

void traverseTopToBottom()

{

struct Node *t;

t=start;

while(t!=NULL)

{

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

t=t->next;

}

}

void traverseBottomToTop(struct Node *t)

{

if(t==NULL)

{

return;

}

traverseBottomToTop(t->next);

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

}

void main()

{

int ch,num,pos;

while(1)

{

printf("\nEnter yours choice\n");

printf("\n1. Add a node at end \n");

printf("\n2. Insert a node at top \n");

printf("\n3. Insert a node at a position\n");

printf("\n4. Remove a node from a position\n");

printf("\n5. Traverse- Top To Bottom\n");

printf("\n6. Traverse- Bottom To Top\n");

printf("\n7. Exit\n");

scanf("%d",&ch);

if(ch==1)

{

printf("Enter a number to add at end:");

scanf("%d",&num);

addAtEnd(num);

}

if(ch==2)

{

printf("Enter a no. to insert at top:");

scanf("%d",&num);

insertAtTop(num);

}

if(ch==3)

{

printf("Enter a no. to insert:");

scanf("%d",&num);

printf("Enter the position: ");

scanf("%d",&pos);

insertAtPosition(num,pos);

}

if(ch==4)

{

printf("Enter position of the node to remove:");

scanf("%d",&pos);

removeFromPosition(pos);

}

if(ch==5)

{

traverseTopToBottom();

}

if(ch==6)

{

traverseBottomToTop(start);

}

if(ch==7)

{

break;

}

}

}