C++/Vector/vector sort

Create const_iterator out of vector of pairs

<source lang="cpp">

1. include <algorithm>
2. include <iostream>
3. include <iterator>
4. include <string>
5. include <vector>
6. include <utility>

using namespace std; typedef pair<int,string> Pair; inline bool less_than_second( const Pair& b1, const Pair& b2 ){

  return b1.second < b2.second;

} int main( ) {

  const char* names[] = { "A","B", "C", "D","E" };
  const int values[] = { 18, 20, 26, 30, 41 };
  const int num_pairs = sizeof( names ) / sizeof( names[0] );
  vector<Pair> pair( num_pairs );
  transform( values, values+num_pairs, names,pair.begin(), make_pair<int,string> );
  sort( pair.begin(), pair.end() );
  sort( pair.begin(), pair.end(), less_than_second );
  vector<Pair>::const_iterator pair_end = pair.end();
  for( vector<Pair>::const_iterator i = pair.begin();
     i != pair_end; ++i )
  cout << i->second << " - $" << i->first << " values\n";

}

 </source>

Create const_reverse_iterator out of vector of pairs

<source lang="cpp">

1. include <algorithm>
2. include <iostream>
3. include <iterator>
4. include <string>
5. include <vector>
6. include <utility>

using namespace std; typedef pair<int,string> Pair; inline bool less_than_second( const Pair& b1, const Pair& b2 ){

  return b1.second < b2.second;

} int main( ) {

  const char* names[] = { "A","B", "C", "D","E" };
  const int values[] = { 18, 20, 26, 30, 41 };
  const int num_pairs = sizeof( names ) / sizeof( names[0] );
  vector<Pair> pair( num_pairs );
  transform( values, values+num_pairs, names,pair.begin(), make_pair<int,string> );
  sort( pair.begin(), pair.end() );
  vector<Pair>::const_reverse_iterator pair_rend = pair.rend();
  
  for( vector<Pair>::const_reverse_iterator i= pair.rbegin(); i != pair_rend; ++i )
     cout << i->first << " - " << i->second;
  sort( pair.begin(), pair.end(), less_than_second );
  vector<Pair>::const_iterator pair_end = pair.end();
  for( vector<Pair>::const_iterator i = pair.begin();
     i != pair_end; ++i )
  cout << i->second << " - $" << i->first << " values\n";

}

 </source>

Loop through a vector in a reversed order

<source lang="cpp">

1. include <algorithm>
2. include <iostream>
3. include <iterator>
4. include <string>
5. include <vector>
6. include <utility>

using namespace std; typedef pair<int,string> Pair; inline bool less_than_second( const Pair& b1, const Pair& b2 ){

  return b1.second < b2.second;

} int main( ) {

  const char* names[] = { "A","B", "C", "D","E" };
  const int values[] = { 18, 20, 26, 30, 41 };
  const int num_pairs = sizeof( names ) / sizeof( names[0] );
  vector<Pair> pair( num_pairs );
  transform( values, values+num_pairs, names,pair.begin(), make_pair<int,string> );
  sort( pair.begin(), pair.end() );
  vector<Pair>::const_reverse_iterator pair_rend = pair.rend();
  
  for( vector<Pair>::const_reverse_iterator i= pair.rbegin(); i != pair_rend; ++i )
     cout << i->first << " - " << i->second;
  sort( pair.begin(), pair.end(), less_than_second );
  vector<Pair>::const_iterator pair_end = pair.end();
  for( vector<Pair>::const_iterator i = pair.begin();
     i != pair_end; ++i )
  cout << i->second << " - $" << i->first << " values\n";

}

 </source>

sort a vector with duplicates

<source lang="cpp">

1. include <algorithm>
2. include <vector>
3. include <string>
4. include <iostream>

int main () {

   using namespace std;
   typedef vector <string> VECTOR_STRINGS;
   VECTOR_STRINGS v;
   v.push_back ("A");
   v.push_back ("B");
   v.push_back ("C");
   v.push_back ("D");
   v.push_back ("D");
   for (size_t nItem = 0; nItem < v.size (); ++ nItem){
       cout << "Name [" << nItem << "] = \"";
       cout << v [nItem] << "\"" << endl;
   }
   sort (v.begin (), v.end ());
   for (size_t nItem = 0; nItem < v.size (); ++ nItem){
       cout << "Name [" << nItem << "] = \"";
       cout << v [nItem] << "\"" << endl;
   }
   return 0;

}

 </source>

Sort elements in a vector with sort(scores.begin(), scores.end());

<source lang="cpp">

1. include <iostream>
2. include <vector>
3. include <algorithm>
4. include <ctime>
5. include <cstdlib>

using namespace std; int main() {

   vector<int>::const_iterator iter;
   vector<int> scores;
   scores.push_back(1);
   scores.push_back(3);
   scores.push_back(5);
   for (iter = scores.begin(); iter != scores.end(); ++iter)
       cout << *iter << endl;
   sort(scores.begin(), scores.end());
   for (iter = scores.begin(); iter != scores.end(); ++iter)
       cout << *iter << endl;
return 0;

}

 </source>