C++ Tutorial/list/list vector — различия между версиями

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Текущая версия на 10:29, 25 мая 2010

assign a list to a vector

#include <list>
#include <vector>
#include <iostream>
using namespace std;
template <class T>
void print(T& c){
   for( typename T::iterator i = c.begin(); i != c.end(); i++ ){
      std::cout << *i << endl;
   }
}
int main( )
{
   const double data[] = { 3.14, 2.78, 1.51, 7.66, 9.65 };
   list<double> original( data, data + sizeof( data ) / sizeof( data[0] ) );
   vector<double> vector_data( 3, 3.33 ); 
   list<double> list_data( 4, 4.44 );
   // show results
   print( original );
   print( vector_data );
   print( list_data );
   // assign a list to a list
   list_data = original;
   // assign a list to a vector
   vector_data.assign( original.begin(), original.end() );
   print( list_data );
   print( vector_data );
 
}

create an empty vector of int"s and assign a list of doubles to it

#include <list>
#include <vector>
#include <iostream>
using namespace std;
template <class T>
void print(T& c){
   for( typename T::iterator i = c.begin(); i != c.end(); i++ ){
      std::cout << *i << endl;
   }
}
int main( )
{
   const double data[] = { 3.14, 2.78, 1.51, 7.66, 9.65 };
   list<double> original( data, data + sizeof( data ) / sizeof( data[0] ) );
   vector<double> vector_data( 3, 3.33 ); 
   list<double> list_data( 4, 4.44 );
   // show results
   print( original );
   print( vector_data );
   print( list_data );
   // assign a list to a list
   list_data = original;
   // create an empty vector of int"s and assign a list of doubles to it
   vector<int> v;
   v.assign( original.begin(), original.end() );
   // show results
   print( list_data );
   print( v );
}

make a vector from a list with vector_copy

#include <iomanip>
#include <iostream>
#include <list>
#include <vector> 
using namespace std;
template <class T>
void print(T& c){
   for( typename T::iterator i = c.begin(); i != c.end(); i++ ){
      std::cout << *i << endl;
   }
}
int main( )
{
   const int data[] = { 1, 1, 2, 3, 5 };
   list<int> original( data,data + sizeof( data ) / sizeof( data[0] ) );
   // make a vector from a list
   vector<int> vector_copy( original.begin(), original.end() );
   // show results
   print( original);
   print( vector_copy);
}

Transfer vector to a list and remove all negative numbers with bind2nd and less

#include <algorithm>
#include <cmath>
#include <functional>
#include <iostream>
#include <list>
#include <numeric>
#include <vector>
using namespace std;
template <class T>
void print(T& c){
   for( typename T::iterator i = c.begin(); i != c.end(); i++ ){
      std::cout << *i << endl;
   }
}
int main( )
{
   const float a[] = { 1, -2.3, 4.5, -6.7, 8.9, 10.2};
   // create and initialize vector with above data
   vector<float> data( a,a + sizeof( a ) / sizeof( a[0] ) );
   cout << "DATA VECTOR HAS " << data.size() << " ELEMENTS\n";
   print( data  );
   // transfer to a list and remove all negative numbers
   list<float> l( data.begin(), data.end() );
   cout << "\nSize of list before calling remove_if: "<< l.size() << endl;
   l.remove_if( bind2nd( less<float>(), 0 ) );
   cout << "Size of list after calling remove_if: " << l.size() << endl;
   print( l );
}

Vector of list of strings

#include <list>
#include <vector>
#include <string>
#include <algorithm>
#include <iterator>
#include <fstream>
#include <iostream>
#include <sstream>
using namespace std;
list<string>
getTotalEnrollment(const vector<list<string> >& classLists,const list<string>& droppedStudents)
{
  list<string> allStudents;
  for (size_t i = 0; i < classLists.size(); ++i) {
    allStudents.insert(allStudents.end(), classLists[i].begin(),classLists[i].end());
  }
  allStudents.sort();
  allStudents.unique();
  for (list<string>::const_iterator it = droppedStudents.begin();
       it != droppedStudents.end(); ++it) {
    allStudents.remove(*it);
  }
  return (allStudents);
}
void readStudentList(list<string> &students, ifstream &istr)
{
  string name;
  while (getline(istr, name)) {
    cout << "Read name " << name << endl;
    students.push_back(name);
  }
}
void readCourseLists(vector<list<string> > &lists){
  for(int i = 1; ; i++) {
    ostringstream ostr;
    ostr << "course" << i << ".txt";
    ifstream istr(ostr.str().c_str());
    if (!istr) {
      cout << "Failed to open " << ostr.str() << endl;
      break;
    }
    list<string> newList;
    readStudentList(newList, istr);
    lists.push_back(newList);
  }
}
void readDroppedStudents(list<string> &students){
  ifstream istr("dropped.txt");
  readStudentList(students, istr);
}
int main(int argc, char **argv)
{
  vector<list<string> > courseLists;
  list<string> droppedStudents;
  readCourseLists(courseLists);
  readDroppedStudents(droppedStudents);
  list<string> finalList = getTotalEnrollment(courseLists, droppedStudents);
  copy(finalList.begin(), finalList.end(), ostream_iterator<string>(cout, "\n"));
}
Источник — «http://cppe.ru/index.php?title=C%2B%2B_Tutorial/list/list_vector&oldid=2392»