englio2.cpp

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// englio2.cpp
// overloaded << and >> operators can work with files
#include <fstream>
#include <iostream>
using namespace std;
////////////////////////////////////////////////////////////////
class Distance                          //English Distance class
   {
   private:
      int feet;
      float inches;
   public:
      Distance() : feet(0), inches(0.0) //constructor (no args)
         {  }                           //constructor (two args)
      Distance(int ft, float in) : feet(ft), inches(in)      
         {  }
      friend istream& operator >> (istream& s, Distance& d);
      friend ostream& operator << (ostream& s, Distance& d);
   };
//--------------------------------------------------------------
istream& operator >> (istream& s, Distance& d)  //get Distance
   {                                            //from file or
   char dummy;  //for ('), (-), and (")         //keyboard
                                                //with
   s >> d.feet >> dummy >> dummy >> d.inches >> dummy;
   return s;                                    //overloaded
   }                                            //>> operator
//--------------------------------------------------------------
ostream& operator << (ostream& s, Distance& d)  //send Distance
   {                                            //to file or
   s << d.feet << "\'-" << d.inches << '\"';    //screen with
   return s;                                    //overloaded
   }                                            //<< operator
////////////////////////////////////////////////////////////////
int main()
   {
   char ch;
   Distance dist1;
   ofstream ofile;                     //create and open
   ofile.open("DIST.DAT");             //output stream

   do {
      cout << "\nEnter Distance: ";
      cin >> dist1;                    //get distance from user
      ofile << dist1;                  //write it to output str
      cout << "Do another (y/n)? ";
      cin >> ch;
      } while(ch != 'n');   
   ofile.close();                      //close output stream

   ifstream ifile;                     //create and open
   ifile.open("DIST.DAT");             //input stream

   cout << "\nContents of disk file is:\n";
   while(true)
      {
      ifile >> dist1;                  //read dist from stream
      if( ifile.eof() )                //quit on EOF
         break;
      cout << "Distance = " << dist1 <<endl;  //display distance
      }
   return 0;
   }