в 14:21, 25 мая 2010

2010-05-25T14:21:06Z

Admin: 1 версия: Импорт контента...

2010-05-25T10:28:01Z

1 версия: Импорт контента...

Новая страница

==access list==

<source lang="cpp">
#include <set>
#include <string>
#include <list>
#include <iostream>
#include <iterator>
using namespace std;
using std::set;
using std::string;
using std::list;
class AccessList
{
public:
AccessList() {}
void addUser(const string& user);
void removeUser(const string& user);
bool isAllowed(const string& user) const;
list<string> getAllUsers() const;
protected:
set<string> mAllowed;
};
void AccessList::addUser(const string& user)
{
mAllowed.insert(user);
}
void AccessList::removeUser(const string& user)
{
mAllowed.erase(user);
}
bool AccessList::isAllowed(const string& user) const
{
return (mAllowed.count(user) == 1);
}
list<string> AccessList::getAllUsers() const
{
list<string> users;
users.insert(users.end(), mAllowed.begin(), mAllowed.end());
return (users);
}
int main(int argc, char** argv)
{
AccessList fileX;
fileX.addUser("A");
fileX.addUser("B");
fileX.addUser("C");
fileX.removeUser("D");
if (fileX.isAllowed("A")) {
cout << "nsolter has permissions\n";
}
if (fileX.isAllowed("B")) {
cout << "baduser has permissions\n";
}
list<string> users = fileX.getAllUsers();
for (list<string>::const_iterator it = users.begin();
it != users.end(); ++it) {
cout << *it << " ";
}
cout << endl;
return (0);
}

</source>

==Add elements in a multiset to a list==

<source lang="cpp">

#include <iostream>
#include <cassert>
#include <list>
#include <string>
#include <set>
using namespace std;
int main()
{
string s("There is no distinctly native American criminal class");
list<char> list1(s.begin(), s.end());
// Put the characters in list1 into multiset1:
multiset<char> multiset1;
list<char>::iterator i;
for (i = list1.begin(); i != list1.end(); ++i)
multiset1.insert(*i);
// Put the characters in multiset1 into list2:
list<char> list2;
multiset<char>::iterator k;
for (k = multiset1.begin(); k != multiset1.end(); ++k)
list2.push_back(*k);

for (i = list2.begin(); i != list2.end(); ++i)
cout << *i;
return 0;
}
/*
ATaaaaccccdeeeehiiiiiiilllmmnnnnnorrrsssstttvy"
*/

</source>

==Add elements in a set to a list==

<source lang="cpp">

#include <iostream>
#include <cassert>
#include <list>
#include <string>
#include <set>
using namespace std;
int main()
{
string s("There is no distinctly native American criminal class");

list<char> list1(s.begin(), s.end());
// Put the characters in list1 into set1:
set<char> set1;
list<char>::iterator i;
for (i = list1.begin(); i != list1.end(); ++i)
set1.insert(*i);
set<char>::iterator j;
list<char> list2;
set<char>::iterator k;
for (k = set1.begin(); k != set1.end(); ++k)
list2.push_back(*k);

for (i = list2.begin(); i != list2.end(); ++i)
cout << *i;
return 0;
}
/*
ATacdehilmnorstvy
*/

</source>

==Comparison Algorithms==

<source lang="cpp">
#include <algorithm>
#include <vector>
#include <list>
#include <iostream>
using namespace std;
int main(int argc, char** argv)
{
vector<int> myVector;
list<int> myList;
myVector.push_back(1);
myVector.push_back(2);
myVector.push_back(3);

myList.push_back(1);
myList.push_back(2);
myList.push_back(3);

if (myList.size() < myVector.size()) {
cout << "Sorry, the list is not long enough.\n";
return (0);
}
if (equal(myVector.begin(), myVector.end(), myList.begin())) {
cout << "The two containers have equal elements\n";
}
if (lexicographical_compare(myVector.begin(), myVector.end(), myList.begin(),myList.end())) {
cout << "The vector is lexicographically first.\n";
} else {
cout << "The list is lexicographically first.\n";
}
return (0);
}

</source>

==Instantiating an STL List of Integers==

<source lang="cpp">
#include <list>
int main ()
{
using namespace std;
list <int> listIntegers;
return 0;
}

</source>

==Merge two lists.==

<source lang="cpp">
#include <iostream>
#include <list>
using namespace std;

int main()
{
list<int> lst1, lst2;
int i;

for(i=0; i<10; i+=2) lst1.push_back(i);
for(i=1; i<11; i+=2) lst2.push_back(i);

list<int>::iterator p = lst1.begin();
while(p != lst1.end()) {
cout << *p << endl;
p++;
}

p = lst2.begin();
while(p != lst2.end()) {
cout << *p << endl;
p++;
}

lst1.merge(lst2);
if(lst2.empty())
cout << "lst2 is now empty\n";

cout << "Contents of lst1 after merge:\n";
p = lst1.begin();
while(p != lst1.end()) {
cout << *p << " ";
p++;
}

return 0;
}

</source>

==Pass list to a function==

<source lang="cpp">

#include <iostream>
using std::cout;
using std::endl;
#include <list> // list class-template definition
#include <algorithm> // copy algorithm
#include <iterator> // ostream_iterator
template < typename T > void printList( const std::list< T > &listRef );
int main()
{
int array[ 4 ] = { 2, 6, 4, 8 };
std::list< int > values; // create list of ints
std::list< int > otherValues; // create list of ints
// insert items in values
values.push_front( 1 );
values.push_front( 2 );
values.push_back( 4 );
values.push_back( 3 );
cout << "values contains: ";
printList( values );
cout << endl;
return 0;
}
template < typename T > void printList( const std::list< T > &listRef )
{
std::ostream_iterator< T > output( cout, " " );
std::copy( listRef.begin(), listRef.end(), output );
}
/*
values contains: 2 1 4 3
*/

</source>

==Store class objects in a list==

<source lang="cpp">

#include <iostream>
#include <list>
#include <cstring>
using namespace std;
class MyClass {
int a, b;
int sum;
public:
MyClass() {
a = b = 0;
}
MyClass(int i, int j) {
a = i;
b = j;
sum = a + b;
}
int getsum() {
return sum;
}
friend bool operator<(const MyClass &o1,const MyClass &o2);
friend bool operator>(const MyClass &o1,const MyClass &o2);
friend bool operator==(const MyClass &o1,const MyClass &o2);
friend bool operator!=(const MyClass &o1,const MyClass &o2);
};
bool operator<(const MyClass &o1, const MyClass &o2)
{
return o1.sum < o2.sum;
}
bool operator>(const MyClass &o1, const MyClass &o2)
{
return o1.sum > o2.sum;
}
bool operator==(const MyClass &o1, const MyClass &o2)
{
return o1.sum == o2.sum;
}
bool operator!=(const MyClass &o1, const MyClass &o2)
{
return o1.sum != o2.sum;
}
int main()
{
list<MyClass> lst1;
for(int i=0; i<10; i++) lst1.push_back(MyClass(i, i));
cout << "First list: ";
list<MyClass>::iterator p = lst1.begin();
while(p != lst1.end()) {
cout << p->getsum() << " ";
p++;
}
cout << endl;
// create a second list
list<MyClass> lst2;
for(int i=0; i<10; i++) lst2.push_back(MyClass(i*2, i*3));
cout << "Second list: ";
p = lst2.begin();
while(p != lst2.end()) {
cout << p->getsum() << " ";
p++;
}
cout << endl;
lst1.merge(lst2);
cout << "Merged list: ";
p = lst1.begin();
while(p != lst1.end()) {
cout << p->getsum() << " ";
p++;
}
return 0;
}
/*
First list: 0 2 4 6 8 10 12 14 16 18
Second list: 0 5 10 15 20 25 30 35 40 45
Merged list: 0 0 2 4 5 6 8 10 10 12 14 15 16 18 20 25 30 35 40 45
*/

</source>

==Store class objects with overloaded operators in a list.==

<source lang="cpp">
#include <iostream>
#include <list>
#include <cstring>
using namespace std;

class myclass {
int a, b;
int sum;
public:
myclass() { a = b = 0; }
myclass(int i, int j) {
a = i;
b = j;
sum = a + b;
}
int getsum() { return sum; }

friend bool operator<(const myclass &o1,const myclass &o2);
friend bool operator>(const myclass &o1,const myclass &o2);
friend bool operator==(const myclass &o1,const myclass &o2);
friend bool operator!=(const myclass &o1,const myclass &o2);
};

bool operator<(const myclass &o1, const myclass &o2)
{
return o1.sum < o2.sum;
}

bool operator>(const myclass &o1, const myclass &o2)
{
return o1.sum > o2.sum;
}

bool operator==(const myclass &o1, const myclass &o2)
{
return o1.sum == o2.sum;
}

bool operator!=(const myclass &o1, const myclass &o2)
{
return o1.sum != o2.sum;
}

int main()
{
int i;

list<myclass> lst1;
for(i=0; i<10; i++) lst1.push_back(myclass(i, i));

list<myclass>::iterator p = lst1.begin();
while(p != lst1.end()) {
cout << p->getsum() << endl;
p++;
}

list<myclass> lst2;
for(i=0; i<10; i++) lst2.push_back(myclass(i*2, i*3));

p = lst2.begin();
while(p != lst2.end()) {
cout << p->getsum() << endl;
p++;
}

// now, merget lst1 and lst2
lst1.merge(lst2);

p = lst1.begin();
while(p != lst1.end()) {
cout << p->getsum() << " ";
p++;
}

return 0;
}

</source>

==Use generic list to create a list of chars==

<source lang="cpp">

#include <iostream>
#include <cassert>
#include <list>
#include <algorithm> // For reverse
using namespace std;

int main()
{
char x[5] = {"a", "b", "c", "d", "e"};
list<char> list1(&x[0], &x[5]);

reverse(list1.begin(), list1.end());
list<char>::iterator i;
cout.precision(10);
for (i = list1.begin(); i != list1.end(); ++i)
cout << *i << endl;
cout << endl;

return 0;
}
/*
e
d
c
b
a
*/

</source>

==Use generic list to create list of strings==

<source lang="cpp">

#include <iostream>
#include <cassert>
#include <list>
#include <algorithm> // For reverse
using namespace std;

int main()
{
string x[5] = {"asdf", "1234", "2345", "6789", "0000"};
list<string> list1(&x[0], &x[5]);

reverse(list1.begin(), list1.end());
list<string>::iterator i;
cout.precision(10);
for (i = list1.begin(); i != list1.end(); ++i)
cout << *i << endl;
cout << endl;

return 0;
}
/*
0000
6789
2345
1234
asdf

*/

</source>

==Uses ostream_iterator and copy algorithm to output list elements==

<source lang="cpp">

#include <iostream>
using std::cout;
using std::endl;
#include <list>
#include <algorithm>
#include <iterator>
template < typename T > void printList( const std::list< T > &listRef );
int main()
{
int array[ 4 ] = { 2, 6, 4, 8 };
std::list< int > values;
std::list< int > otherValues;
values.push_front( 1 );
values.push_front( 2 );
values.push_back( 4 );
values.push_back( 3 );
cout << "values contains: ";
printList( values );
cout << endl;
return 0;
}
template < typename T > void printList( const std::list< T > &listRef )
{
std::ostream_iterator< T > output( cout, " " );
std::copy( listRef.begin(), listRef.end(), output );
}
/*
values contains: 2 1 4 3
*/

</source>

==Use std::copy to print all elements in a list==

<source lang="cpp">

#include <iostream>
using std::cout;
using std::endl;
#include <list> // list class-template definition
#include <algorithm> // copy algorithm
#include <iterator> // ostream_iterator
int main()
{
int array[ 4 ] = { 2, 6, 4, 8 };
std::list< int > values; // create list of ints
std::list< int > otherValues; // create list of ints
// insert items in values
values.push_front( 1 );
values.push_front( 2 );
values.push_back( 4 );
values.push_back( 3 );
cout << "values contains: ";
std::ostream_iterator< int > output( cout, " " );
std::copy( values.begin(), values.end(), output );
cout << endl;
return 0;
}
/*
values contains: 2 1 4 3
*/

</source>

==Using the list as a container for double value==

<source lang="cpp">
#include <iostream>
#include <list>
#include <numeric>
using namespace std;
void print(const list<double> &lst)
{
list<double>::const_iterator p;
for (p = lst.begin();
p !=lst.end(); ++p)
cout << *p << endl;
cout << endl;
}
int main()
{
double w[4] = { 0.9, 0.8, 88, -99.99 };
list<double> z;
for( int i = 0; i < 4; ++i)
z.push_front(w[i]);
print(z);
z.sort();
print(z);
cout << "sum is "
<< accumulate(z.begin(), z.end(), 0.0)
<< endl;
}

</source>

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

C++/List/list - История изменений

в 14:21, 25 мая 2010

Admin: 1 версия: Импорт контента...