C++ Tutorial/STL Algorithms Modifying sequence operations/swap

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Illustrating the generic swap algorithm

<source lang="cpp">#include <iostream>

  1. include <cassert>
  2. include <algorithm>
  3. include <vector>

using namespace std; int main() {

 vector<int> vector1(100, 1), vector2(200, 2);
 swap(vector1, vector2);
 for(int i=0;i<vector1.size();i++){
    cout << vector1[i] ;
 }
 cout << "\n\n\n\n\n";
 for(int i=0;i<vector2.size();i++){
    cout << vector2[i] ;
 }
 return 0;

}</source>

22222222222222222222222222222222222222222222222222222222222222222222222222222222
22222222222222222222222222222222222222222222222222222222222222222222222222222222
2222222222222222222222222222222222222222


11111111111111111111111111111111111111111111111111111111111111111111111111111111
11111111111111111111

Illustrating the generic swap algorithm: swap two integers

<source lang="cpp">#include <iostream>

  1. include <cassert>
  2. include <algorithm>
  3. include <vector>

using namespace std; int main() {

 int high = 250, low = 0;
 swap(high, low);
 cout << high << " ";
 cout << low;
 return 0;

}</source>

0 250

Swap elements at locations 0 and 1 of an array

<source lang="cpp">#include <iostream> using std::cout; using std::endl;

  1. include <algorithm>
  2. include <iterator>

int main() {

  int a[ 10 ] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
  std::ostream_iterator< int > output( cout, " " );
  cout << "Array a contains:\n   ";
  std::copy( a, a + 10, output );
  
  std::swap( a[ 0 ], a[ 1 ] );
  cout << "\nArray a after swapping a[0] and a[1] using swap:\n   ";
  std::copy( a, a + 10, output ); // display array a
  cout << endl;
  return 0;

}</source>

Array a contains:
   1 2 3 4 5 6 7 8 9 10
Array a after swapping a[0] and a[1] using swap:
   2 1 3 4 5 6 7 8 9 10

Swap second and fourth element in a vector

<source lang="cpp">/* The following code example is taken from the book

* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/
  1. include <iostream>
  2. include <vector>
  3. include <string>
  4. include <algorithm>
  5. include <iterator>

using namespace std; int main() {

   // create empty vector for strings
   vector<string> sentence;
   // reserve memory for five elements to avoid reallocation
   sentence.reserve(5);
   // append some elements
   sentence.push_back("Hello,");
   sentence.push_back("how");
   sentence.push_back("are");
   sentence.push_back("you");
   sentence.push_back("?");
   // swap second and fourth element
   swap (sentence[1], sentence[3]);
   // print elements separated with spaces
   copy (sentence.begin(), sentence.end(),
         ostream_iterator<string>(cout," "));
   cout << endl;

}</source>

Hello, you are how ?