в 14:21, 25 мая 2010

2010-05-25T14:21:06Z

Admin: 1 версия: Импорт контента...

2010-05-25T10:27:57Z

1 версия: Импорт контента...

Новая страница

==Sort objects stored in deque==

<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.
*/
#include <iostream>
#include <string>
#include <deque>
#include <set>
#include <algorithm>
using namespace std;

/* class Person
*/
class Person {
private:
string fn; // first name
string ln; // last name
public:
Person() {
}
Person(const string& f, const string& n)
: fn(f), ln(n) {
}
string firstname() const;
string lastname() const;
// ...
};
inline string Person::firstname() const {
return fn;
}
inline string Person::lastname() const {
return ln;
}
ostream& operator<< (ostream& s, const Person& p)
{
s << "[" << p.firstname() << " " << p.lastname() << "]";
return s;
}

/* binary function predicate:
* - returns whether a person is less than another person
*/
bool personSortCriterion (const Person& p1, const Person& p2)
{
/* a person is less than another person
* - if the last name is less
* - if the last name is equal and the first name is less
*/
return p1.lastname()<p2.lastname() ||
(p1.lastname()==p2.lastname() &&
p1.firstname()<p2.firstname());
}
int main()
{
// create some persons
Person p1("nicolai","josuttis");
Person p2("ulli","josuttis");
Person p3("anica","josuttis");
Person p4("lucas","josuttis");
Person p5("lucas","otto");
Person p6("lucas","arm");
Person p7("anica","holle");

// insert person into collection coll
deque<Person> coll;
coll.push_back(p1);
coll.push_back(p2);
coll.push_back(p3);
coll.push_back(p4);
coll.push_back(p5);
coll.push_back(p6);
coll.push_back(p7);
// print elements
cout << "deque before sort():" << endl;
deque<Person>::iterator pos;
for (pos = coll.begin(); pos != coll.end(); ++pos) {
cout << *pos << endl;
}
// sort elements
sort(coll.begin(),coll.end(), // range
personSortCriterion); // sort criterion
// print elements
cout << "deque after sort():" << endl;
for (pos = coll.begin(); pos != coll.end(); ++pos) {
cout << *pos << endl;
}
}
/*
deque before sort():
[nicolai josuttis]
[ulli josuttis]
[anica josuttis]
[lucas josuttis]
[lucas otto]
[lucas arm]
[anica holle]
deque after sort():
[lucas arm]
[anica holle]
[anica josuttis]
[lucas josuttis]
[nicolai josuttis]
[ulli josuttis]
[lucas otto]
*/
</source>

==Use sorting criterion in sort function==

<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.
*/
#include <iostream>
#include <vector>
#include <deque>
#include <list>
#include <set>
#include <map>
#include <string>
#include <algorithm>
#include <iterator>
#include <functional>
#include <numeric>
/* PRINT_ELEMENTS()
* - prints optional C-string optcstr followed by
* - all elements of the collection coll
* - separated by spaces
*/
template <class T>
inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="")
{
typename T::const_iterator pos;
std::cout << optcstr;
for (pos=coll.begin(); pos!=coll.end(); ++pos) {
std::cout << *pos << " ";
}
std::cout << std::endl;
}
/* INSERT_ELEMENTS (collection, first, last)
* - fill values from first to last into the collection
* - NOTE: NO half-open range
*/
template <class T>
inline void INSERT_ELEMENTS (T& coll, int first, int last)
{
for (int i=first; i<=last; ++i) {
coll.insert(coll.end(),i);
}
}
using namespace std;
void printCollection (const list<int>& l)
{
PRINT_ELEMENTS(l);
}
bool lessForCollection (const list<int>& l1, const list<int>& l2)
{
return lexicographical_compare
(l1.begin(), l1.end(), // first range
l2.begin(), l2.end()); // second range
}
int main()
{
list<int> c1, c2, c3, c4;
// fill all collections with the same starting values
INSERT_ELEMENTS(c1,1,5);
c4 = c3 = c2 = c1;
// and now some differences
c1.push_back(7);
c3.push_back(2);
c3.push_back(0);
c4.push_back(2);
// create collection of collections
vector<list<int> > cc;
cc.push_back(c1);
cc.push_back(c2);
cc.push_back(c3);
cc.push_back(c4);
cc.push_back(c3);
cc.push_back(c1);
cc.push_back(c4);
cc.push_back(c2);
// print all collections
for_each (cc.begin(), cc.end(),
printCollection);
cout << endl;
// sort collection lexicographically
sort (cc.begin(), cc.end(), // range
lessForCollection); // sorting criterion
// print all collections again
for_each (cc.begin(), cc.end(),
printCollection);
}
/*
1 2 3 4 5 7
1 2 3 4 5
1 2 3 4 5 2 0
1 2 3 4 5 2
1 2 3 4 5 2 0
1 2 3 4 5 7
1 2 3 4 5 2
1 2 3 4 5
1 2 3 4 5
1 2 3 4 5
1 2 3 4 5 2
1 2 3 4 5 2
1 2 3 4 5 2 0
1 2 3 4 5 2 0
1 2 3 4 5 7
1 2 3 4 5 7
*/

</source>

← Предыдущая	Версия 14:21, 25 мая 2010
(нет различий)

C++/STL Algorithms Sorting/custom comparer - История изменений

в 14:21, 25 мая 2010

Admin: 1 версия: Импорт контента...