🚀 Programming Example
Program of queue using linked list
Program of queue using linked list
/* Program of queue using linked list*/
#include<stdio.h>
#include<stdlib.h>
struct node
{
int info;
struct node *link;
}*front=NULL,*rear=NULL;
void insert(int item);
int del();
int peek();
int isEmpty();
void display();
main()
{
int choice,item;
while(1)
{
printf("1.Insert\n");
printf("2.Delete\n");
printf("3.Display the element at the front\n");
printf("4.Display all elements of the queue\n");
printf("5.Quit\n");
printf("Enter your choice : ");
scanf("%d", &choice);
switch(choice)
{
case 1:
printf("Input the element for adding in queue : ");
scanf("%d",&item);
insert(item);
break;
case 2:
printf("Deleted element is %d\n",del());
break;
case 3:
printf("Element at the front of the queue is %d\n", peek() );
break;
case 4:
display();
break;
case 5:
exit(1);
default :
printf("Wrong choice\n");
}/*End of switch*/
}/*End of while*/
}/*End of main()*/
void insert(int item)
{
struct node *tmp;
tmp=(struct node *)malloc(sizeof(struct node));
if(tmp==NULL)
{
printf("Memory not available\n");
return;
}
tmp->info = item;
tmp->link=NULL;
if(front==NULL) /*If Queue is empty*/
front=tmp;
else
rear->link=tmp;
rear=tmp;
}/*End of insert()*/
int del()
{
struct node *tmp;
int item;
if( isEmpty( ) )
{
printf("Queue Underflow\n");
exit(1);
}
tmp=front;
item=tmp->info;
front=front->link;
free(tmp);
return item;
}/*End of del()*/
int peek()
{
if( isEmpty( ) )
{
printf("Queue Underflow\n");
exit(1);
}
return front->info;
}/*End of peek()*/
int isEmpty()
{
if(front==NULL)
return 1;
else
return 0;
}/*End of isEmpty()*/
void display()
{
struct node *ptr;
ptr=front;
if(isEmpty())
{
printf("Queue is empty\n");
return;
}
printf("Queue elements :\n\n");
while(ptr!=NULL)
{
printf("%d ",ptr->info);
ptr=ptr->link;
}
printf("\n\n");
}/*End of display()*/
1.Insert
2.Delete
3.Display the element at the front
4.Display all elements of the queue
5.Quit
Enter your choice : 1
Input the element for adding in queue : 12
1.Insert
2.Delete
3.Display the element at the front
4.Display all elements of the queue
5.Quit
Enter your choice : 1
Input the element for adding in queue : 13
1.Insert
2.Delete
3.Display the element at the front
4.Display all elements of the queue
5.Quit
Enter your choice : 4
Queue elements :
12 13
1.Insert
2.Delete
3.Display the element at the front
4.Display all elements of the queue
5.Quit
Enter your choice : 2
Deleted element is 12
1.Insert
2.Delete
3.Display the element at the front
4.Display all elements of the queue
5.Quit
Enter your choice : 4
Queue elements :
13
1.Insert
2.Delete
3.Display the element at the front
4.Display all elements of the queue
5.Quit
Enter your choice : 5
Press any key to continue . . .
First understand the algorithm carefully. Then study the program line-by-line and compare it with the output. Finally, review the explanation section to strengthen your logic and programming understanding.
Rewrite the program without looking at the code. Modify values, conditions or logic and run it again. This helps improve confidence and strengthens coding skills much faster.