fig14_08.paul

经典vc教程的例子程序

// fig14_8.cpp
// Credit inquiry program
#include <iostream.h>
#include <fstream.h>
#include <iomanip.h>
#include <stdlib.h> 

void outputLine( int, char*, double );

main()
{
   ifstream inClientFile( "clients.dat", ios::in );

   if ( !inClientFile ) {
      cerr << "File could not be opened" << endl;
      exit( 1 );
   }

   cout << "Enter request\n"
        << " 1 - List accounts with zero balances\n"
        << " 2 - List accounts with credit balances\n"
        << " 3 - List accounts with debit balances\n" 
        << " 4 - End of run\n? ";

   int request;
   cin >> request;

   while ( request != 4 ) {
      int account;
      char name[ 10 ];
      double balance;

      inClientFile >> account >> name >> balance;

      switch (request) {
         case 1:
            cout << endl << "Accounts with zero balances:" << endl;

            while (!inClientFile.eof()) {
               if (balance == 0)
                  outputLine(account, name, balance);

               inClientFile >> account >> name >> balance;
            }

            break;
         case 2:
            cout << endl << "Accounts with credit balances:" 
                 << endl;

            while (!inClientFile.eof()) {
               if (balance < 0)
                  outputLine(account, name, balance);

               inClientFile >> account >> name >> balance;
            }

            break;
         case 3:
            cout << endl << "Accounts with debit balances:" 
                 << endl;

            while (!inClientFile.eof()) {
               if (balance > 0)
                  outputLine(account, name, balance);

               inClientFile >> account >> name >> balance;
            }

            break;
      }

      inClientFile.clear();  // reset eof for next input
      inClientFile.seekg(0); // position to beginning of file
      cout << endl << "? ";
      cin >> request;
   }

   cout << "End of run." << endl;

   return 0;
}

void outputLine(int acct, char *name, double bal)
{
   cout << setiosflags(ios::left) << setw(10) << acct
        << setw(13) << name << setw(7) << setprecision(2)
        << setiosflags(ios::showpoint | ios::right)
        << bal << endl;
}