Mistake in display and insert methods (double-ended queue)
- by MANAL
1) My problem
when i make remove from right or left program will be remove true
but when i call diplay method the content wrong
like this
I insert 12 43 65 23
and when make remove from left program will remove 12
but when call display method show like this 12 43 65
and when make remove from right program will remove 23
but when call display method show like this 12 43
Why ?????? );
and when i try to make insert after remove write this
Can not insert right because the queue is full . first remove right and then u can insert right
where is the problem ??
Please Help me
please
2) My code
FIRST CLASS
class dqueue
{
private int fullsize; //number of all cells
private int item_num; // number of busy cells only
private int front,rear;
public int j;
private double [] dqarr;
//==========================================
public dqueue(int s) //constructor
{
fullsize = s;
front = 0;
rear = -1;
item_num = 0;
dqarr = new double[fullsize];
}
//==========================================
public void insert(double data)
{
if (rear == fullsize-1)
rear = -1;
rear++;
dqarr[rear] = data;
item_num++;
}
public double removeLeft() // take item from front of queue
{
double temp = dqarr[front++]; // get value and incr front
if(front == fullsize)
front = 0;
item_num --; // one less item
return temp;
}
public double removeRight() // take item from rear of queue
{
double temp = dqarr[rear--]; // get value and decr rear
if(rear == -1) //
rear = item_num -1;
item_num --; // one less item
return temp;
}
//=========================================
public void display () //display items
{
for (int j=0;j<item_num;j++) // for every element
System.out.print(dqarr[j] +" " ); // display it
System.out.println("");
}
//=========================================
public int size() //number of items in queue
{
return item_num;
}
//==========================================
public boolean isEmpty() // true if queue is empty
{
return (item_num ==0);
}
}
SECOND CLASS
import java.util.Scanner;
class dqueuetest
{
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
System.out.println(" ***** Welcome here***** ");
System.out.println(" ***** Mind Of Programming Group***** ");
System.out.println(" _____________________________________________ ");
System.out.println("enter size of your dqueue");
int size = input.nextInt();
dqueue mydq = new dqueue(size);
System.out.println("");
System.out.println("enter your itemes");
//=====================================
for(int i = 0;i<=size-1;i++)
{
System.out.printf("item %d:",i+1);
double item = input.nextDouble();
mydq.insert(item);
System.out.println("");
}
//=====================================
int queue =size ;
int c = 0 ;
while (c != 6)
{
System.out.println("");
System.out.println("************************************************");
System.out.println(" MAIN MENUE");
System.out.println("1- INSERT RIGHT ");
System.out.println("2- REMOVE LEFT");
System.out.println("3- REMOVE RIGHT");
System.out.println("4- DISPLAY");
System.out.println("5- SIZE");
System.out.println("6- EXIT");
System.out.println("************************************************");
System.out.println("choose your operation by number(1-6)");
c = input.nextInt();
switch (c)
{
case 1:
if (queue == size)
System.out.print("Can not insert right because the queue is full . first remove right and then u can insert right ");
else { System.out.print("enter your item: ");
double item = input.nextDouble();
mydq.insert(item);}
break;
case 2:
System.out.println("REMOVE FROM REAR :");
if( !mydq.isEmpty() )
{
double item = mydq.removeLeft();
System.out.print(item + "\t");
} // end while
System.out.println("");
mydq.display();
break;
case 3:
System.out.println("REMOVE FROM FRONT :");
if( !mydq.isEmpty() )
{
double item = mydq.removeRight();
System.out.print(item + "\t");
} // end while
System.out.println("");
mydq.display();
break;
case 4:
System.out.println("The items in Queue are :");
mydq.display();
break;
case 5:
System.out.println("The Size of the Queue is :"+mydq.size());
break;
case 6:
System.out.println("Good Bye");
break;
default:
System.out.println("wrong chiose enter again");
} //end switch
} //end while
} // end main
}//end class
