Merging two lists (STL)

vegaseat 2 Tallied Votes 184 Views Share

Let's say you worked in the White House and had to keep two lists, one for the friends and one for the enemies. The boss came to you and said: "The Almighty talked to me out of a burning bush last night, telling me that I shall make my enemies my friends! Can you help me?"

// merge two STL lists 
// using list from the Standard Template Libraries
// a Dev-C++ tested console application

#include <iostream>
#include <list>        // list header
#include <iterator>    // ostream_iterator

static char friends[6][15]=
{
  "Britain","Israel","Italy","Lichtenstein",
  "Poland","Upper Volta"
};

static char enemies[8][15]=
{
  "France","China","Germany","Spain",
  "Canada","Iran","Brazil","Syria"
};

using namespace std;

int main()
{
  int k;
  list<string> fL;
  list<string> eL; 
  
  // load the f list
  for(int k = 0; k < 6; k++)
  {
    fL.push_back(friends[k]);
  }
  cout << "The friends list:\n";
  // print out the list one item on a line
  copy(fL.begin(),fL.end(),ostream_iterator<string>(cout,"\n"));
  
  // load the e list
  for(int k = 0; k < 8; k++)
  {
    eL.push_back(enemies[k]);
  }
  cout << "The enemies list:\n";
  // print out the list one item on a line
  copy(eL.begin(),eL.end(),ostream_iterator<string>(cout,"\n"));

  // make 'em all friends, sort 'em to be impartial
  // merge() does sort the resulting list, list eL is now empty 
  fL.merge(eL);
  cout << "The new friends list (sorted):\n";
  // print out the list one item on a line
  copy(fL.begin(),fL.end(),ostream_iterator<string>(cout,"\n"));        
    
  cin.get();   // wait
  return 0;
}
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