queue.cpp

queue.cpp

@@ -0,0 +1,105 @@
+#include <cstdio>
+#include <iostream>
+using namespace std;
+
+struct node
+{	int data;
+	node*next;
+}*front,*rear;
+
+class queue
+{
+public:
+	queue()
+	{	front=rear=NULL;
+	}
+void insert(int x)
+{	node*n=new node;
+	n->data=x;
+	n->next=NULL;
+	if(rear==NULL)
+		rear=front=n;
+	else
+	{	rear->next=n;
+		rear=n;
+	}
+}
+int remove()
+{	if(front==NULL)
+	return(0);
+	if(front==rear)
+	{	delete front;
+		front=rear=NULL;
+		return(1);
+	}
+	node*r;
+	r=front;
+	front=front->next;
+	delete r;
+	return(1);
+}
+int count();
+void display();
+};
+int queue::count()
+{  	int c=0;
+	if(front==NULL)
+	return(c);
+	node*t;
+	t=front;
+	while(t!=rear)
+	{ 	 t=t->next;
+		 c++;
+	}
+	c++;
+	return(c);
+}
+
+void queue::display()
+{	if(front==NULL)
+	{
+	cout<<"empty";
+	exit(0);
+	}
+	else
+	{	node*s;
+		s=front;
+		while(s!=NULL)
+		{	cout<<s->data<<"-";
+			s=s->next;
+		}
+	}
+}
+
+int main()
+{	queue list;
+	int n,r;
+	char c;
+	do
+	{
+	cout<<"ENter your choice 1.ins 2.rem 3.disp\n";
+	cin>>n;
+	switch(n)
+	{
+	 case 1:
+		cout<<"enter roll no : ";
+		cin>>r;
+		list.insert(r);
+		break;
+
+	 case 2:
+		list.remove();
+		break;
+
+	 case 3:
+		list.display();
+		break;
+
+	 default :
+	  exit(0);
+	  }
+	  cout<<"Do you wish to continue('y/Y') : ";
+	  cin>>c;
+	  }while(c=='y'||c=='Y');
+	return 0;
+}