const double value : const « Language Basics « C++ Tutorial

1. C++ Tutorial
2. Language Basics
3. const

#include <iostream>

using namespace std;

int main()
{  
   double bottles;

   cout << "How many bottles do you have? ";
   cin >> bottles;

   double cans;
   cout << "How many cans do you have? ";
   cin >> cans;

   const double BOTTLE_VOLUME = 2.0;
   const double CAN_VOLUME = 0.355;
   double total = bottles * BOTTLE_VOLUME 
      + cans * CAN_VOLUME;

   cout << "The total volume is " << total << " liter.\n";

   return 0;
}