C++/Set Multiset/multiset iterator
iterator that cannot be used to change element values in multiset
<source lang="cpp">
- include <iostream>
using std::cout; using std::endl;
- include <set> // multiset class-template definition
- include <algorithm> // copy algorithm
- include <iterator> // ostream_iterator
int main() {
int a[ 10 ] = { 7, 22, 9, 1, 18, 30, 100, 22, 85, 13 }; std::multiset< int, std::less< int > > intMultiset; std::ostream_iterator< int > output( cout, " " ); intMultiset.insert( 15 ); intMultiset.insert( 15 );
// iterator that cannot be used to change element values std::multiset< int, std::less< int > >::const_iterator result; // find 15 in intMultiset; find returns iterator result = intMultiset.find( 15 ); if ( result != intMultiset.end() ) // if iterator not at end cout << "Found value 15\n"; // found search value 15 cout << endl; return 0;
}
/*
Found value 15
*/ </source>
multiset<User Object>::const_iterator
<source lang="cpp">
- include <algorithm>
- include <functional>
- include <iostream>
- include <set>
- include <string>
- include <utility>
- include <vector>
using namespace std; class Dog {
public: Dog( string name = "Unknown", string breed = "A",int year = 2000 ); bool operator<( const Dog& rhs ) const; string breed() const; string name() const; void print() const; int year() const; private: string breed_; string name_; int year_;
}; inline Dog::Dog( string name, string breed, int year )
: breed_( breed ), name_( name ), year_( year )
{} // empty inline bool Dog::operator<( const Dog& rhs ) const { return name() < rhs.name(); } inline string Dog::breed() const { return breed_; } inline string Dog::name() const { return name_; } inline void Dog::print() const {
cout << name() << ", a " << breed() << ", won in " << year() << endl;
} inline int Dog::year() const { return year_; } bool equal_breed( const Dog winner, string breed );
int main( ) {
const char* breed[] = { "A","B", "C","D", "E" }; const char* name[] = { "a","b", "c","d", "e" }; const int year[] = { 1971, 1972, 1973, 1974, 1975 }; const int num_dogs = sizeof( breed ) / sizeof( breed[0] ); vector<Dog> v; for( int i = 0; i < num_dogs; ++i ) v.push_back( Dog( name[i], breed[i], year[i] ) ); const Dog query( "A" ); cout << query.name(); set<Dog> winner_set( v.begin(), v.end() ); set<Dog>::const_iterator winner_set_end = winner_set.end(); // search in the set by value set<Dog>::const_iterator spot = winner_set.find( query ); if( spot != winner_set_end ) spot->print(); else cout << query.name() << " never won best-in-show\n"; const string query_breed( "A" ); for( spot = winner_set.begin(); spot != winner_set_end; ++spot ) if( spot->breed() == query_breed ) break;
} inline bool equal_breed( const Dog winner, string breed ) { return winner.breed() == breed; }
</source>