Merge pull request #271 from nirmalkatiyar/master

Added new data structure Deque.

Author: master-fury

Data_Structure/src/Queue/Dequeue.cpp

@@ -0,0 +1,121 @@
+#include<iostream>
+using namespace std;
+#define SIZE 10
+class dequeue {
+   int a[20],f,r;//f==front r== rear
+   public:
+      dequeue();
+      void insert_at_beg(int);
+      void insert_at_end(int);
+      void delete_fr_front();
+      void delete_fr_rear();
+      void show();
+};
+dequeue::dequeue() {
+   f=-1;
+   r=-1;
+}
+void dequeue::insert_at_end(int i) {
+   if(r>=SIZE-1) {
+      cout<<"\n insertion is not possible, overflow!!!!";
+   } else {
+      if(f==-1) {
+         f++;
+         r++;
+      } else {
+         r=r+1;
+      }
+      a[r]=i;
+      cout<<"\nInserted item is"<<a[r];
+   }
+}
+void dequeue::insert_at_beg(int i) {
+   if(f==-1) {
+      f=0;
+      a[++r]=i;
+      cout<<"\n inserted element is:"<<i;
+   } else if(f!=0) {
+      a[--f]=i;
+      cout<<"\n inserted element is:"<<i;
+   } else {
+      cout<<"\n insertion is not possible, overflow!!!";
+   }
+}
+void dequeue::delete_fr_front() {
+   if(f==-1) {
+      cout<<"deletion is not possible::dequeue is empty";
+      return;
+   }
+   else {
+      cout<<"the deleted element is:"<<a[f];
+      if(f==r) {
+         f=r=-1;
+         return;
+      } else
+         f=f+1;
+      }
+   }
+   void dequeue::delete_fr_rear() {
+      if(f==-1) {
+         cout<<"deletion is not possible::dequeue is empty";
+         return;
+      }
+      else {
+         cout<<"the deleted element is:"<<a[r];
+         if(f==r) {
+            f=r=-1;
+         } else
+            r=r-1;
+      }
+   }
+   void dequeue::show() {
+      if(f==-1) {
+         cout<<"Dequeue is empty";
+      } else {
+         for(int i=f;i<=r;i++) {
+            cout<<a[i]<<" ";
+         }
+      }
+   }
+   int main() {
+      int c,i;
+      dequeue d;
+      //perform switch opeartion 
+      do {
+      cout<<"\n 1.insert at beginning";
+      cout<<"\n 2.insert at end";
+      cout<<"\n 3.show";
+      cout<<"\n 4.deletion from front";
+      cout<<"\n 5.deletion from rear";
+      cout<<"\n 6.exit";
+      cout<<"\n enter your choice:";
+      cin>>c;
+      switch(c) {
+         case 1:
+            cout<<"enter the element to be inserted";
+            cin>>i;
+            d.insert_at_beg(i);
+         break;
+         case 2:
+            cout<<"enter the element to be inserted";
+            cin>>i;
+            d.insert_at_end(i);
+         break;
+         case 3:
+            d.show();
+         break;
+         case 4:
+            d.delete_fr_front();
+         break;
+         case 5:
+            d.delete_fr_rear();
+         break;
+         case 6:
+            exit(1);
+         break;
+         default:
+            cout<<"invalid choice";
+         break;
+      }
+   } while(c!=7);
+}