deque::front and deque::back

Illustrates how to use the deque::front and deque::back Standard Template Library (STL) functions in Visual C++.

reference front( );
   const_reference front( ) const;
reference back( );
   const_reference back( ) const;

Remarks

Observação

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

The front member function returns a reference to the first element of the controlled sequence, which must be nonempty. The back member function returns a reference to the last element of the controlled sequence, which must be nonempty.

Example

// front.cpp
// compile with: /EHsc
#include <iostream>
#include <deque>
using namespace std;
typedef deque<char >  CHARDEQUE;
void print_contents (CHARDEQUE  deque, char*);

int main()
{
   //create a  with  A, B, C and D
   CHARDEQUE  a;
   a.push_back('A');
   a.push_back('B');
   a.push_back('C');
   a.push_back('D');

   //print out the contents
   print_contents (a,"a");
   cout <<"The first element of a is " <<a.front() <<endl;
   cout <<"The last element of a is " <<a.back() <<endl;

   // modify first and last elements using reference, front, and back
   CHARDEQUE::reference reffront=a.front();
   CHARDEQUE::reference refback=a.back();

   reffront='X';
   refback='Y';
   print_contents (a,"a");
}

// 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;
}

The contents of a: A B C D
The first element of a is A
The last element of a is D
The contents of a: X B C Y

Requirements

Header: <deque>

See Also

Concepts

Standard Template Library Samples