C++ programming language

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(Default Arguments)

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1. �� . �� overfun.cpp �� . 3 �� . �� . �� - void box_display(), void box_display(char ch) � void box_display(char ch, int n).

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// overfun_def.cpp
// default argument function instead of oberloaded functions

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

const int MAX_LENGTH = 40; // maximum length of text

class fancy_text                    // class displays text
{
   private:
      char text[MAX_LENGTH];        // text to be displayed

   public:
      void set_text(char tx[])      // set the text
      {
         strcpy(text, tx);
      }

      // default line of MAX_LENGTH dashes
      // or line of MAX_LENGTH other symbols
      void box_display(char ch = '-', int n = MAX_LENGTH);
};

// line of n characters
// no default arguments are given in the definition
void fancy_text::box_display(char ch, int n)
{
int j;

for (j = 0; j < n; j++)
cout << ch;

cout << endl << text << endl;

for (j = 0; j < n; j++)
cout << ch;
}

void main()
{
fancy_text ft1;

ft1.set_text("Gone with the Wind");

   // display text with default lines
   ft1.box_display();
   cout << endl << endl;

   // default length and equal signs
   ft1.box_display('+');
   cout << endl << endl;

   // equal signs; length matches text
   ft1.box_display('=', 18);
   cout << endl << endl;

getch();

} // main()

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Default argument value redeclared for parameter 'ch'.

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void badfunc(int, int=2, int); // no good

void okfunc(int, int=2, int=10); // ok

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----------------------------------------
Gone with the Wind
----------------------------------------

++++++++++++++++++++++++++++++++++++++++
Gone with the Wind
++++++++++++++++++++++++++++++++++++++++

==================
Gone with the Wind
==================

2. �� (The cin.getline() Function). � �� cin.get(), �� . �� cin.getline() � �� - �� 80 �� str:

cin.getline(str, 80); // get up to 80 chars, place in str

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// get up to 80 chars or until encounter $ sign, place in str
cin.getline(str, 80, '$');

�� $ �� . �� cin.getline() �� IOSTREAM.H � �� :

istream getline(char, int, char = '\n'); // simplified declaration

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[1] Robert Lafore; C⁺⁺ Interactive Course. Waite Group Press, Macmillan Computer Publishing, 1996.
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[ �� 26 �� 2008 � - �� 2009 � �� "��" www.kosnos.com ]

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