INFO: STL Sample for deque:: assign and deque::swap Functions

MORE INFORMATION

Required Header

   < deque>
				

Prototype

   void assign(const_iterator first, const_iterator last);
   void assign(size_type n, const T& x = T());
   void swap(deque& dq);
				

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

The swap member function swaps the contents between *this and dq.

Sample Code

////////////////////////////////////////////////////////////////////// 
// 
// Compile options needed: -GX
// 
// deque.cpp :
// 
// Functions:
// 
//    assign
//    swap
//    begin
//    end
// 
// Written by Bobby Mattappally
// of Microsoft Product Support Services,
// Copyright (c) 1996 Microsoft Corporation. All rights reserved.
////////////////////////////////////////////////////////////////////// 

/* Compile options needed:-GX
*/ 
#include <iostream>
#include <deque>

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

typedef deque<char, allocator<char> >  CHARDEQUE;

void print_contents (CHARDEQUE  deque, char*);

void main()

{

    //create a  with  3 A's
    CHARDEQUE  a(3,'A');

    //create b with 4 B's.
    CHARDEQUE  b(4,'B');

    //print out the contents
    print_contents (a,"a");
    print_contents (b,"b");

    //swap a and b
    a.swap(b);
    print_contents (a,"a");
    print_contents (b,"b");

    // let us swap it back
        a.swap(b);
    print_contents (a,"a");
    print_contents (b,"b");

    //assign the contents of b to a
    a.assign(b.begin(),b.end());
    print_contents (a,"a");

    //assign the first two items of b to a
    a.assign(b.begin(),b.begin()+2);
    print_contents (a,"a");

    //assign 3 'Z's to a
    a.assign(3,'Z');
    print_contents (a,"a");

    }

//function to print the contents of deque
void print_contents (CHARDEQUE  deque, char *name)

{

    CHARDEQUE::iterator pdeque;

    cout <<"The contents of "<< name <<" : ";

        for(pdeque = deque.begin();
        pdeque != deque.end();
        pdeque++)
    {
        cout << *pdeque <<" " ;
    }
        cout<<endl;

}
				

Program Output is:

The contents of a : A A A
The contents of b : B B B B
The contents of a : B B B B
The contents of b : A A A
The contents of a : A A A
The contents of b : B B B B
The contents of a : B B B B
The contents of a : B B
The contents of a : Z Z Z