/* Program to implement queue using linked list */
#include
#include
#define new1 (nd *)malloc(sizeof(nd))
typedef struct queue
{
int info;
struct queue *next;
}nd;
void display(nd *ptr)
{
if(ptr==NULL)
printf("\nQueue is empty...\n");
else
{
printf("\nQueue : ");
while(ptr!=NULL)
{
printf(" %d --> ",ptr->info);
ptr=ptr->next;
}
printf("\b\b\b\b ");
printf("\n");
}
}
void insert(nd **ptr)
{
nd *c=*ptr;
if(*ptr==NULL)
{
*ptr=new1;
printf("\nEnter the element : ");
scanf("%d",&(*ptr)->info);
(*ptr)->next=NULL;
}
else
{
nd *t;
t=new1;
printf("\nEnter the element : ");
scanf("%d",&t->info);
while(c->next!=NULL)
c=c->next;
t->next=NULL;
c->next=t;
}
}
void delete(nd **ptr)
{
nd *c=*ptr,*t=*ptr;
if(*ptr==NULL)
printf("\nQueue is empty...");
else if(t->next==NULL) // If queue contains single node
{
*ptr=NULL;
free(t);
}
else
{
*ptr=c->next;
free(c);
}
}
main()
{
nd *h=NULL;
printf("\nProgram to implement queue using linked list : \n");
int ch;
do
{
printf("\n[1] Insert [2] Delete [3] Display [4] Exit : \n");
printf("\nEnter your choice : ");
scanf("%d",&ch);
switch(ch)
{
case 1:
insert(&h);
display(h);
break;
case 2:
delete(&h);
display(h);
break;
case 3:
display(h);
break;
case 4:
break;
default : printf("\nEnter correct choice : \n");
break;
}
}while(ch!=4);
}
