fig17_07.cpp

是有关C++编程原理教程的例子程序,全,应该对大家有所帮助

// Fig. 17.7: Fig17_07.cpp
// Reading and printing a sequential file.
#include <iostream>
using std::cerr;
using std::cout;
using std::endl;
using std::fixed;
using std::ios;
using std::left;
using std::right;
using std::showpoint;

#include <fstream> // file stream
using std::ifstream; // input file stream

#include <iomanip>
using std::setw;
using std::setprecision;

#include <string>
using std::string;

#include <cstdlib> 
using std::exit; // exit function prototype

void outputLine( int, const string, double ); // prototype

int main()
{
   // ifstream constructor opens the file          
   ifstream inClientFile( "clients.dat", ios::in );

   // exit program if ifstream could not open file
   if ( !inClientFile ) 
   {
      cerr << "File could not be opened" << endl;
      exit( 1 );
   } // end if

   int account;
   char name[ 30 ];
   double balance;

   cout << left << setw( 10 ) << "Account" << setw( 13 ) 
      << "Name" << "Balance" << endl << fixed << showpoint;

   // display each record in file
   while ( inClientFile >> account >> name >> balance )
      outputLine( account, name, balance );

   return 0; // ifstream destructor closes the file
} // end main

// display single record from file
void outputLine( int account, const string name, double balance )
{
   cout << left << setw( 10 ) << account << setw( 13 ) << name
      << setw( 7 ) << setprecision( 2 ) << right << balance << endl;
} // end function outputLine

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