05:05 - 
Data Structures using C
Data Structures using C
Implement the following basic operations on double ended queues: a) Insertion at the rear end b) Insertion at the front end
a) insertion at the rear end on a double ended queue
/*function
to insert an item at the rear end on a double ended queue*/
void
insert_rear(int item, int q[], int *r)
{
if (qfull(*r))/*check if queue is full*/
{
printf(“Queue Overflow\n”);
}
/*queue is not full*/
q[++(*r)]= item;
}
/*function
to check whether queue is full*/
int
qfull(int r)
{ /*returns true if queue is full otherwise
false*/
return ( r==queue_size-1)?1:0;
}
b)
Insertion at the front end on a double ended queue
/*function
to insert an item at the from end on a double ended queue*/
void
insert_front(int item,int q[], int *f, int *r)
{
if ( *f ==0 && *r==-1)
q[++(*r)]=item;
else if ( *f !-0)
q[--(*f)]=itme;
else
printf(“Front insertion not
possible\n”);
}
/*main()
function to implement these function*/
#include<stdio.h>
#include<process.h>
#define
QUEUE_SIZE 5
void
main()
{
int
choice,item,f,r,q[10];
f=0,
r=-1;
for(;;)
{
printf(“1: Insert at Front End\n”);
printf(“2: Insert at Front End\n”);
scanf(“%d”,&choice);
switch(choice)
{
case 1:
printf(“Enter the item to be
inserted\n”);
scanf(“%d”,&item);
insert_front(item,q,&f,&r);
break;
case 2:
printf(“Enter the item to be
inserted\n”);
scanf(“%d”,&item);
insert_rear(item,q,&r);
break;
default:
exit(0);
}
}
}