C++ programming language

�� C⁺⁺
�� 20

�� 
(Arrays of Strings)

�� , �� , ��, �� .

1. �� . �� , �� . �� 10 �� 20 ��, �� .

char names[10][20]; // array of 10 strings

�� , �� (� �� 10) �� . �� , �� j, �� names[j]: �� , �� 0, �.�. �� j �� j+1 ��. �� 10 �� (�� -�� , �� ):

for (j = 0; j < 10; j++)
{
cout << �Enter name (or press Enter to exit loop): �;
cin.get(names[j], 10);
if (strlen(names[j]) == 0) // if user presses [Enter],
break; // exit from loop
}

2. �� . �� , �� . �� :

const int MAX = 10; // maximum length of day name, +1
const int DPW = 7; // days per week

// array of day names
const char day_name[DPW][MAX] = { "Sunday", "Monday", "Tuesday",
"Wednesday", "Thursday", "Friday",
"Saturday"};

�� . �� const � ��, �� , �� .

3. �� , �� . �� [1]. �� , �� MAX � �� , �.�. � �� -�� -�� ("Wednesday"), �� , '\0', � �� -- �� .

�� day_name, �� (external variable), �� . �� day_name � ��, �� (static variable) - � �� . �� .

// weekdays.cpp
// creates a class of days of the week objects

#include <iostream.h>
#include <string.h> // for stricmp()
#include <conio.h> // for getch()

const int MAX = 10; // maximum length of day name, +1
const int DPW = 7; // days per week

// array of day names
const char day_name[DPW][MAX] = { "Sunday", "Monday", "Tuesday",
"Wednesday","Thursday", "Friday",
"Saturday"};

class weekday // class of day names
{
private:
int day_number; // Sunday = 0, etc.

public:
    void inday()                   // user inputs day name
    {
      char tempday[MAX];           // holds user input
      int gotit = 0;               // match found? (0 = false)
      int j;                       // loop variable

      while( !gotit )              // cycle until user enters
      {                            // a correct name
        cout << "Enter day of week (e.g., Friday): ";

cin >> tempday;

        for (j = 0; j < DPW; j++)       // compare user input
        {                          // with list of names
          if (stricmp(tempday, day_name[j]) == 0)
          {                        // if there's a match,
            gotit = 1;             // set flag,
            break;                 // break out of for loop
          }
        } // end for

        day_number = j;            // record what day it was
      } // end while
    } // end inday()

    void outday()                  // display the day name
    {
      cout << day_name[day_number];
    }

    void outnumber()               // display the day number
    {
      cout << (day_number + 1);
    }

    void add(int days)             // add days to
    {                              // this weekday
      day_number += days;          // add days
      day_number %= DPW;           // ensure not > 7
    }
}; // end weekdays class

////////////////////////////////////////////////////////////////
void main()
{
weekday wd; // make a weekday object

cout << "What day is it?" << endl;
wd.inday(); // user gives it a value

cout << "You entered ";
wd.outday(); // display its day name

cout << "\nThat's day number ";
wd.outnumber(); // display its day number

wd.add(10); // add 10 days to it
cout << "\nTen days later is ";
wd.outday(); // display its day name

// added to stop the output onto the monitor
getch();
} // main()

� �� , day_number, �� (�� , �� !) � �� : inday(), outday(), outnumber() � add(int days). �� , �� , �� , �� , �� , � �� "��" �� , �.�. �� .

� �� , main(), �� weekday, �� , �� (wd.add(10);) � �� .

4. �� . 3. �� inday() �� stricmp(tempday, day_name[j]), �� tempday � day_name[j] � �� 0, �� . �� strcmp, �� (ignores case) � �� "Monday" � "monday" �� .

�� add(int days), �� ��  (Arithmetic Assignment Operator) +=, �� . �.�. day_number += days; � �� day_number = day_number + days;, � day_number %= DPW; - �� day_number = day_number%DPW;: �� , �� % �� .

� C⁺⁺ �� :

a += b;    // same as a = a + b
a -= b;    // same as a = a - b
a *= b;    // same as a = a * b
a /= b;    // same as a = a / b
a %= b;    // same as a = a % b

�� (�� "��"):

What day is it?
Enter day of week (e.g., Friday): monday
You entered Monday
That's day number 2
Ten days later is Thursday

�� -�� -��, �� C⁺⁺.

� �� -- �� (enum) � �� (bool).

.
^{(��)}
.
��
. [1] Robert Lafore; C⁺⁺ Interactive Course. Waite Group Press, Macmillan Computer Publishing, 1996.

��: ��. ��

[ �� 22 �� 2008 �. �� "��" www.kosnos.com ]

Keywords: �++, OOP programming , C++ , Classes , Inheritance , Reusability , Creating New Data Types , Polymorphism and Overloading
�� : �� , ��, �� , �� switch if else ?