Implements queue class as a template, uses exceptions to handle errors in queue - C++ template

C++ examples for template:template class

  1. HOME
  2. C++
  3. template
  4. template class

Description

Implements queue class as a template, uses exceptions to handle errors in queue

Demo Code

#include <iostream>
using namespace std;
const int MAX = 3;
template <class Type>
class Queue/*from w w w.ja v a  2s  . co m*/
{
   private:
   Type qu[MAX]; //array of any type
   int head;     //index of front of queue (remove old item)
   int tail;     //index of back of queue (insert new item)
   int count;    //number of items in queue
   public:
   class full  {  };          //exception classes
   class empty  {  };
   Queue()                    //constructor
   { head = -1; tail = -1; count = 0; }
   void put(Type var)         //insert item at queue tail
   {
      if(count >= MAX)        //if queue already full,
         throw full();        //   throw exception
      qu[++tail] = var;       //store item
      ++count;
      if(tail >=MAX-1)        //wrap around if past array end
         tail = -1;
   }
   Type get()                 //remove item from queue head
   {
         if(count <= 0)          //if queue empty,
            throw empty();       //   throw exception
         Type temp = qu[++head]; //get item
         --count;
         if(head >= MAX-1)       //wrap around if past array end
            head = -1;
         return temp;            //return item
   }
};
int main()
{
      Queue<float> q1;     //q1 is object of class Queue<float>
      float data;          //data item obtained from user
      char choice = 'p';   //'x', 'p' or 'g'
      do                   //do loop (enter 'x' to quit)
      {
         try               //try block
         {
            cout << "\nEnter 'x' to exit, 'p' for put, 'g' for get: ";
            cin >> choice;
            if(choice=='p')
            {
               cout << "Enter data value: ";
               cin >> data;
               q1.put(data);
            }
            if(choice=='g')
               cout << "Data=" << q1.get() << endl;
         }  //end try
         catch(Queue<float>::full)
         {
               cout << "Error: queue is full." << endl;
         }
         catch(Queue<float>::empty)
         {
               cout << "Error: queue is empty." << endl;
         }
      } while(choice != 'x');
      return 0;
}

Result


Related Tutorials