HOWTO: STL Sample for list::size,list::resize Functions

MORE INFORMATION

Required Header

   <list>
   <string>
   <iostream>
				

Prototype

   size_type max_size() const;
   size_type size() const;
   void resize(size_type n, T x = T());
				

NOTE: The class/parameter names in the prototype may not match the version in the header file. Some have been modified to improve readability.

Description

The member function max_size returns the length of the longest sequence that the object can control. The member function size returns the length of the controlled sequence. The member function resize ensures that size() henceforth returns n. If the member function resize must make the controlled sequence longer, it appends elements with the value x.

Sample Code

////////////////////////////////////////////////////////////////////// 
// 
// Compile options needed: -GX
// 
// size.cpp :  This example shows how to resize a list<T>.  It also
//             uses list::size() and list::max_size().
// 
//  Functions
//  ---------
// 
//  list::size
//  list::resize
//  list::max_size
// 
// Written by Andrew Bradnan
// Copyright (c) 1996 Microsoft Corporation. All rights reserved.
////////////////////////////////////////////////////////////////////// 

    #include <list>
    #include <string>
    #include <iostream>
    
   #if _MSC_VER > 1020   // if VC++ version is > 4.2
   using namespace std;  // std c++ libs implemented in std
   #endif


    typedef list<string, allocator<string> > LISTSTR;

    void main()
    {
       LISTSTR test;
       LISTSTR::iterator i;

       cout << "max_size() = " << test.max_size() << endl;

       test.insert(test.begin(), 10, "test");

       cout << "There are " << test.size() << " elements." << endl;
       // test test test test test test test test test test
       for (i = test.begin(); i != test.end(); ++i)
          cout << *i << " ";
       cout << endl;

       // Make it smaller
       test.resize(5);
       cout << "There are " << test.size() << " elements." << endl;
       // test test test test test
       for (i = test.begin(); i != test.end(); ++i)
          cout << *i << " ";
       cout << endl;

       // Make it bigger
       test.resize(10, "bigger");
       // test test test test test bigger bigger bigger bigger bigger
       cout << "There are " << test.size() << " elements." << endl;
       for (i = test.begin(); i != test.end(); ++i)
          cout << *i << " ";
       cout << endl;

       test.clear();
       cout << "There are " << test.size() << " elements." << endl;
    }
				

The Program Output is:

    max_size() = 268435455
    There are 10 elements.
    test test test test test test test test test test
    There are 5 elements.
    test test test test test
    There are 10 elements.
    test test test test test bigger bigger bigger bigger bigger
    There are 0 elements.