Code

struct deque
{
   int* values;
   int start;
   int end;
   int capacity;
   int size;

   deque(int size)
   {
     capacity = size;
     values = new int[capacity];
     start = 0;
     end = 0;
     size = 0;
   }

   void push_front(int item)
   {
     values[start] = item;
     start = (start + 1) % capacity;
     size++;
   }

   void push_back(int item)
   {
     values[end] = item;
     end = (end - 1 + capacity) % capacity;
     size++;
   }

   void pop_front(void)
   {
       start = (start - 1 + capacity) % capacity;
       size--;
   }


   void pop_end(void)
   {
       end = (end + 1) % capacity;
       size--;
   }
};