1   // Fig. 14.7: Fig14_07.cpp
 2   // Credit inquiry program.
 3   #include <iostream>
 4   #include <fstream>  
 5   #include <iomanip>
 6   #include <string>
 7   #include <cstdlib>
 8   using namespace std;
 9
10   enum RequestType { ZERO_BALANCE = 1, CREDIT_BALANCE, DEBIT_BALANCE, END };
11   int getRequest();
12   bool shouldDisplay( int, double );
13   void outputLine( int, const string &, double );
14
15   int main()
16   {
17      // ifstream constructor opens the file          
18      ifstream inClientFile( "clients.txt", ios::in );
19
20      // exit program if ifstream could not open file
21      if ( !inClientFile )
22      {
23         cerr << "File could not be opened" << endl;
24         exit( EXIT_FAILURE );
25      } // end if
26
27      int account; // the account number
28      string name; // the account owner's name
29      double balance; // the account balance
30
31      // get user's request (e.g., zero, credit or debit balance)
32      int request = getRequest();
33
34      // process user's request
35      while ( request != END )
36      {
37         switch ( request )
38         {
39            case ZERO_BALANCE:
40               cout << " Accounts with zero balances: ";
41               break;
42            case CREDIT_BALANCE:
43               cout << " Accounts with credit balances: ";
44               break;
45            case DEBIT_BALANCE:
46               cout << " Accounts with debit balances: ";
47               break;
48         } // end switch
49
50         // read account, name and balance from file
51         inClientFile >> account >> name >> balance;
52
53         // display file contents (until eof)
54         while ( !inClientFile.eof() )
55         {
56            // display record
57            if ( shouldDisplay( request, balance ) )
58               outputLine( account, name, balance );
59
60            // read account, name and balance from file
61            inClientFile >> account >> name >> balance;
62         } // end inner while
63
64         inClientFile.clear(); // reset eof for next input          
65         inClientFile.seekg( 0 ); // reposition to beginning of file
66         request = getRequest(); // get additional request from user
67      } // end outer while
68
69      cout << "End of run." << endl;
70   } // end main
71
72   // obtain request from user
73   int getRequest()
74   {
75      int request; // request from user
76
77      // display request options
78      cout << " Enter request" << endl
79         << " 1 - List accounts with zero balances" << endl
80         << " 2 - List accounts with credit balances" << endl
81         << " 3 - List accounts with debit balances" << endl
82         << " 4 - End of run" << fixed << showpoint;
83
84      do // input user request
85      {
86         cout << " ? ";
87         cin >> request;
88      } while ( request < ZERO_BALANCE && request > END );
89
90      return request;
91   } // end function getRequest
92
93   // determine whether to display given record
94   bool shouldDisplay( int type, double balance )
95   {
96      // determine whether to display zero balances
97      if ( type == ZERO_BALANCE && balance == 0 )
98         return true;
99
100     // determine whether to display credit balances
101     if ( type == CREDIT_BALANCE && balance < 0 )
102        return true;
103
104     // determine whether to display debit balances
105     if ( type == DEBIT_BALANCE && balance > 0 )
106        return true;
107
108     return false;
109  } // end function shouldDisplay
110
111  // display single record from file
112  void outputLine( int account, const string &name, double balance )
113  {
114     cout << left << setw( 10 ) << account << setw( 13 ) << name
115        << setw( 7 ) << setprecision( 2 ) << right << balance << endl;
116  } // end function outputLine