INFO: (push_back, pop_back) Functions

ID: Q158620

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 following sample code illustrates how to use the vector::push_back and vector::pop_back STL functions in Visual C++.

MORE INFORMATION

Required Header


   <vector>

Prototypes


   template<class _TYPE, class _A>
   void vector::push_back(const _TYPE& X);

   template<class _TYPE, class _A>
   void vector::pop_back();

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 sample declares an empty vector of integers. It adds three integers to the vector, and then deletes one. Finally, it generates the remaining elements in the vector.

Sample Code


////////////////////////////////////////////////////////////////////// 
// 
// Compile options needed: /GX
// 
// Pushpop.cpp: Illustrates how to use the push and pop member
//              functions of the vector container.
// 
// Functions:
// 
//    vector::push_back - Appends (inserts) an element to the end of a
//                        vector, allocating memory for it if necessary.
// 
//    vector::pop_back -  Erases the last element of the vector.
// 
//    vector::begin - Returns an iterator to start traversal of the vector.
// 
//    vector::end - Returns an iterator for the last element of the vector.
// 
//    vector::iterator - Traverses the vector.
// 
// Written by Tom Campbell
// of Microsoft Corporation
// Copyright (c) 1996 Microsoft Corporation. All rights reserved.
////////////////////////////////////////////////////////////////////// 

// The debugger can't handle symbols more than 255 characters long.
// STL often creates symbols longer than that.
// When symbols are longer than 255 characters, the warning is disabled.

#pragma warning(disable:4786)

#include <iostream>
#include <vector>

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

typedef vector<int, allocator<int> > INTVECTOR;

void main()

{

    // Dynamically allocated vector begins with 0 elements.
    INTVECTOR theVector;

    // Iterator is used to loop through the vector.
    INTVECTOR::iterator theIterator;

    // Add one element to the end of the vector, an int with the value 42.
    // Allocate memory if necessary.
    theVector.push_back(42) ;

    // Add two more elements to the end of the vector.
    // theVector will contain [ 42, 1, 109 ].
    theVector.push_back(1) ;
    theVector.push_back(109) ;

    // Erase last element in vector.
    theVector.pop_back();

    // Output contents of theVector. Shows [ 42, 1 ]
    cout << "theVector [ " ;
    for (theIterator = theVector.begin(); theIterator != theVector.end();
         theIterator++)
    {
        cout << *theIterator;
        if (theIterator != theVector.end()-1) cout << ", ";
                                              // cosmetics for the output
    }
    cout << " ]" << endl ;

}

Program Output


theVector [ 42, 1 ]

REFERENCES

Visual C++ Books Online: Visual C++ Books; C/C++; Standard C++ Library Reference

Additional query words: STL STLSample

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