Exercise 3
b) Consider a payment counter at which the customer pays for the items purchased. Every time a
customer finished paying for their items, he/she leaves the queue from the front. Every time
another customer enters the line to wait, they join the end of the line. Implement the application
for this problem.
Aim::/*To implement queue at payment counter*/
Program::
#include< stdio.h> //Standard i/p,o/p header file
voidfill(); //prototype of function enque
void delete();
void display();
int queue[20],remv[20],temp[20]; //Declaration of array
int f=-1,r=-1; //f-front,r-rear intialisation
int int h,i,n,t,j; //h-for switch case,n-for size of queue
int main() //main function
{
printf("Enter the size of queue : ");
scanf("%d",&n);
while(h!=4)
{
printf(" 1-for insert\n 2-for delete \n 3-for display \n 4-for exit \n Enter ur choice: ");
scanf("%d",&h);
switch(h)
{
case 1:fill(); //calling function
break;
case 2:delete();
break;
case 3:display();
break;
case 4:
break;
default:printf("Invalid entry \n");
}
}
}
void fill()
{
j=0;
if(r==n-1)
{
printf("Queue is full \n");
display();
printf("wait for sometime to send another person \n");
}
else
{
r++;
if(f< 0||queue[r-1]< n)
queue[r]=queue[r-1]+1;
else if(queue[r-1]>=n ||queue[r-2]>=n)
{
queue[r]=remv[j];
j++;
f--;
}
printf("Filled position is %d \n",queue[r]);
}
}
void delete()
{
if(r==-1)
printf("Queue is empty deletion not possible\n");
else
{
f++;
remv[f]=queue[0];
printf("The removed position is %d \n",remv[f]);
// printf("%d \t %d",f,remv[f]);
t=r;
}
for(i=0;i<=t;i++)
{
queue[i]=queue[i+1];
}
r--;
}
void display()
{
printf("\n The filled positions in the queue are \n");
if(r==-1)
printf(" Null \n");
else
{
t=r;
for(i=0;i<=t;i++)
printf("%d \t",queue[i]);
printf("\n");
}
printf("\n Th1e vacant positions in the queue are \n");
if(r==n-1)
printf(" Null \n");
else
{
temp[0]=queue[r];
i=-1;
for(j=1;j< n-r;j++)
{
temp[j]=temp[j-1]+1;
if(temp[j]>n)
{
i++;
printf("%d \t",remv[i]);
}
if(temp[j-1]<=n-1)
{
printf("%d\t ",temp[j]=temp[j-1]+1);
}
}
}
printf("\n");
}
output::
Enter the size of queue : 7
1-for insert
2-for delete
3-for display
4-for exit
Enter ur choice: 1
Filled position is 1
1-for insert
2-for delete
3-for display
4-for exit
Enter ur choice: 1
Filled position is 2
1-for insert
2-for delete
3-for display
4-for exit
Enter ur choice: 1
Filled position is 3
1-for insert
2-for delete
3-for display
4-for exit
Enter ur choice: 1
Filled position is 4
1-for insert
2-for delete
3-for display
4-for exit
Enter ur choice: 3
The filled positions in the queue are
1 2 3 4
Th1e vacant positions in the queue are
5 6 7
1-for insert
2-for delete
3-for display
4-for exit
Enter ur choice: 2
The removed position is 1
1-for insert
2-for delete
3-for display
4-for exit
Enter ur choice: 2
The removed position is 2
1-for insert
2-for delete
3-for display
4-for exit
Enter ur choice: 2
The removed position is 3
1-for insert
2-for delete
3-for display
4-for exit
Enter ur choice: 2
The removed position is 4
1-for insert
2-for delete
3-for display
4-for exit
Enter ur choice: 3
The filled positions in the queue are
Null
Th1e vacant positions in the queue are
1 2 3 4 5 6 7
1-for insert
2-for delete
3-for display
4-for exit
Enter ur choice:4
