INFO: STL Sample for the list::assign Functions

ID: Q158085

The information in this article applies to:

The Standard C++ Library, used with:
- Microsoft Visual C++, 32-bit Editions, versions 4.2, 5.0, 6.0

SUMMARY

The sample code below illustrates how to use the list::assign, list::empty, and list::erase STL functions in Visual C++.

MORE INFORMATION

Required Header


   <list>

Prototype


   void assign(const_iterator first, const_iterator last);
   void assign(size_type n, const T& x = T());
   iterator erase(iterator it);
   iterator erase(iterator first, iterator last);
   bool empty() const;

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 first member function replaces the sequence controlled by *this with the sequence [first, last). The second member function replaces the sequence controlled by *this with a repetition of n elements of value x.

The third member function removes the element of the controlled sequence pointed to by it. The fourth member function removes the elements of the controlled sequence in the range [first, last). Both return an iterator that designates the first element remaining beyond any elements removed, or end() if no such element exists.

The last member function returns true for an empty controlled sequence.

Sample Code


////////////////////////////////////////////////////////////////////// 
// 
// Compile options needed: -GX
// 
// assign.cpp :  Shows the various ways to assign and erase elements
//               from a list<T>.
// 
// Functions:
// 
//    list::assign
//    list::empty
//    list::erase
// 
// Written by Andrew Bradnan
// Copyright (c) 1996 Microsoft Corporation. All rights reserved.
////////////////////////////////////////////////////////////////////// 

#include <list>
#include <iostream>

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

typedef list<int, allocator<int> > LISTINT;

void main()

{

    LISTINT listOne;
    LISTINT listAnother;
    LISTINT::iterator i;

    // Add some data
    listOne.push_front (2);
    listOne.push_front (1);
    listOne.push_back (3);

    listAnother.push_front(4);

    listAnother.assign(listOne.begin(), listOne.end());

    // 1 2 3
    for (i = listAnother.begin(); i != listAnother.end(); ++i)
        cout << *i << " ";
    cout << endl;

    listAnother.assign(4, 1);

    // 1 1 1 1
    for (i = listAnother.begin(); i != listAnother.end(); ++i)
        cout << *i << " ";
    cout << endl;

    listAnother.erase(listAnother.begin());

    // 1 1 1
    for (i = listAnother.begin(); i != listAnother.end(); ++i)
        cout << *i << " ";
    cout << endl;

    listAnother.erase(listAnother.begin(), listAnother.end());
    if (listAnother.empty())
        cout << "All gone\n";

}

Program Output is:


1 2 3
1 1 1 1
1 1 1
All gone

REFERENCES

Visual C++ Books On Line: Visual C++ Books:C/C++:Standard C++ Library Reference.

Additional query words: STL STLSample list::assign list::empty list::erase

Keywords : kbcode kbVC420 kbVC500 kbVC600 kbDSupport STLIss
Version : winnt:4.2,5.0,6.0
Platform : winnt
Issue type : kbinfo