A program to implement Circular Queues in arrays. The program has four options as given below and it continues till the user wants
a) Insert
b) Delete
c) Display
d) Exit

 

#include<iostream.h>
#include<stdio.h>
#include<conio.h>

int queue[10];
int front=0,rear=0;

void insert()
{
if((front==0 && rear==9) || (rear==front-1))
{
cout<<"\nQueue Overflow.\n\n";
}
else
{
if(rear<9)
{
rear++;
cout<<"\nEnter Data: ";
cin>>queue[rear];
}
else
{
rear=0;
cout<<"\nEnter Data: ";
cin>>queue[rear];
}
cout<<endl;
}
}

void del()
{
if(rear==front)
cout<<"\nQueue Underflow.\n\n";
else
{
if(front<9)
{
front++;
cout<<"\nDeleted value: "<<queue[front]<<"\n\n";
}
else
{
front=0;
cout<<"\nDeleted value: "<<queue[front]<<"\n\n";
}
}
}

void display()
{
int j;

if(front!=rear)
{
cout<<"\nQueue: ";
if(front<rear)
{
for(int i=front+1;i<=rear;i++)
{
cout<<queue[i]<<" ";
}
}
else
{
for(j=front+1;j <9;j++)
cout<<queue[j]<<" ";
for(j=0;j<rear;j++)
cout<<queue[j]<<" ";
}
cout<<"\n\n";
}
else
cout<<"\nQueue empty.\n\n";
}

void main()
{
 clrscr();
 int ch;

 do 
  {
   cout<<"1.Insert"<<endl;
   cout<<"2.Delete"<<endl;
   cout<<"3.Display"<<endl;
   cout<<"4.Exit"<<endl;
   cout<<"Enter your choice: ";
   cin>>ch;

   switch(ch)
    {
     case 1: {
                  insert();
                  break;
                 }
     case 2: {
                  del();
                  break;
                 }
     case 3: {
                  display();
                  break;
                 }
     case 4: {
                  break;
                 }
      default:{
                  cout<<"\nWrong choice entered.\n\n";
                 }
    }
  }
 while(ch!=4);
}

 

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