01: #include <iostream>
02: #include <iomanip>
03: #include <fstream>
04: #include <sstream>
06: using namespace std;
07: 
08: #include "ccc_empl.cpp"
09: 
10: const int NEWLINE_LENGTH = 2; /* or 1 on Unix */
11: const int RECORD_SIZE = 30 + 10 + NEWLINE_LENGTH;
13: /** 
14:    Converts a string to a floating-point value, e.g. 
15:    "3.14" -> 3.14.
16:    @param s a string representing a floating-point value
17:    @return the equivalent floating-point value
18: */   
19: double string_to_double(string s)
20: {  istringstream instr(s);
22:    double x;
23:    instr >> x;
24:    return x;
25: }
27: /** 
28:    Raises an employee salary.
29:    @param e employee receiving raise
30:    @param percent the percentage of the raise
31: */
32: void raise_salary(Employee& e, double percent)
33: {  double new_salary = e.get_salary() * (1 + percent / 100);
35:    e.set_salary(new_salary);
36: }
38: /**
39:    Reads an employee record from a file.
40:    @param e filled with the employee
41:    @param in the stream to read from
42: */
43: void read_employee(Employee& e, istream& in)
44: {  string line;
46:    getline(in, line);
47:    if (in.fail()) return;
48:    string name = line.substr(0, 30);
49:    double salary = string_to_double(line.substr(30, 10));
50:    e = Employee(name, salary);
51: }
53: /**
54:    Writes an employee record to a stream
55:    @param e the employee record to write
56:    @param out the stream to write to
57: */
58: void write_employee(Employee e, ostream& out)
59: { out << e.get_name()
61:       << setw(10 + (30 - e.get_name().length()))
62:       << fixed << setprecision(2)
63:       << e.get_salary() << "\n";
65: }
67: int main()
68: {  cout << "Please enter the data file name: ";
70:    string filename;
71:    cin >> filename;
72:    fstream fs;
73:    fs.open(filename.c_str());
74:    fs.seekg(0, ios::end); /* go to end of file */
75:    int nrecord = fs.tellg() / RECORD_SIZE;
76: 
77:    cout << "Please enter the record to update: (0 - "
78:         << nrecord - 1 << ") ";
79:    int pos;
80:    cin >> pos;
81: 
82:    const double SALARY_CHANGE = 5.0;
83: 
84:    Employee e;
85:    fs.seekg(pos * RECORD_SIZE, ios::beg);
86:    read_employee(e, fs);
87:    raise_salary(e, SALARY_CHANGE);
88:    fs.seekp(pos * RECORD_SIZE, ios::beg);
89:    write_employee(e, fs);
90: 
91:    fs.close();
92:    return 0;
93: }