Multimap
Multimap, map gibi çalışır fakat ek olarak, aynı ada sahip birden fazla ögenin varlığına da izin verir.
Multimap vs Map
Örnek
#include <iostream>
#include <map>
struct Nokta { double x, y; };
struct NoktaCmp {
bool operator()(const Nokta& lhs, const Nokta& rhs) const {
return lhs.x < rhs.x; // NB. ignores y on purpose
}
};
int main() {
std::multimap<int, int> multimap1 = {{1,2},{2,1},{3,3},{7,4},{4,5},{4,4},{3,3},{2,2},{3,3}}; //Multimap ile uye atamasi.
for(auto& p: multimap1)
std::cout << p.first << ' ' << p.second << '\n';
std::multimap<Nokta, double, NoktaCmp> multimap2{
{ {8, 12}, 15 },
{ {4, 7}, 7 },
{ {8, 15}, 17 },
{ {3, -3}, -5 },
}; //Multimap ile uye atamasi.
for(auto p : multimap2)
std::cout << "(" << p.first.x
<< ", " << p.first.y << ") is "
<< p.second << '\n';
}Çıktı:
Örnek
#include <map>
#include <iostream>
/**
* Multimap kopyalama ve tasima islemi yapilmistir.
*/
using namespace std;
void boyutuYazdir(const multimap<int,int> &sayilar1,
const multimap<int,int> &sayilar2,
const multimap<int,int> &sayilar3)
{
cout << "sayilar1: " << sayilar1.size()
<< " sayilar2: " << sayilar2.size()
<< " sayilar3: " << sayilar3.size() << '\n';
}
//size(): Boyutu dondurur.
int main()
{
std::multimap<int, int> sayilar1 {{3, 1}, {4, 1}, {5, 9},
{6, 1}, {7, 1}, {8, 9}};
std::multimap<int, int> sayilar2;
std::multimap<int, int> sayilar3;
cout << "Tanimlanan:\n";
boyutuYazdir(sayilar1, sayilar2, sayilar3);
sayilar2 = sayilar1;
cout << "Kopyalanan:\n";
boyutuYazdir(sayilar1, sayilar2, sayilar3);
sayilar3 = move(sayilar1);
//move(): Yollanani tasir.
cout << "Tasinan:\n";
boyutuYazdir(sayilar1, sayilar2, sayilar3);
}Çıktı:
Tanimlanan: sayilar1: 6 sayilar2: 0 sayilar3: 0 Kopyalanan: sayilar1: 6 sayilar2: 6 sayilar3: 0 Tasinan: sayilar1: 0 sayilar2: 6 sayilar3: 6
Örnek
#include <map>
#include <iostream>
#include <utility>
int main()
{
std::multimap<int, int> sayilar;
std::cout << "Bos mu?: " << sayilar.empty() << std::endl; //1 ise bos
//empty(): Eleman olup olmadigini kontrol eder.
sayilar.emplace(42, 13);
//emplace(): Kurucu ile dogrudan atama.
sayilar.insert(std::make_pair(13317, 123));
//insert(): pair olarak olusturulan multimap e eklenir.
std::cout << "Bos mu?: " << sayilar.empty() << std::endl; //1 ise bos
std::cout << "Boyut: " << sayilar.size() << std::endl;
//size(): Boyutu dondurur.
std::cout << "Tanimlanabilecek en buyuk boyut: " << sayilar.max_size() << std::endl;
//max_size():Tanimlanabilecek en buyuk boyutu dondurur.
sayilar.clear();
//Multimap in bütün elemanlarini siler.
std::cout << "Boyut: " << sayilar.size() << std::endl;
}Çıktı:
Örnek
#include <map>
#include <iostream>
int main()
{
std::multimap<int, std::string> sayi = {{1, "bir"}, {2, "iki"}, {3, "uc"},
{4, "dort"}, {5, "bes"}, {6, "alti"}};
for(auto i = sayi.begin(); i != sayi.end(); )
if(i->first % 2 == 1) //tek sayilari sil
i = sayi.erase(i);
//erase(): Eleman silme islemi.
else
++i;
for(auto& p : sayi)
std::cout << p.second << ' ';
}Çıktı:
Örnek
#include <iostream>
#include <map>
int main()
{
std::multimap<int,char> aranacak = {{1,'a'},{2,'b'}};
auto ara = aranacak.find(2);
//find(): Gonderilen anahtari elemanlarda ara.
if(ara != aranacak.end()) {
//end(): Map in son elemanini dondurur.
std::cout << "Bulundu: " << ara->first << " " << ara->second << std::endl ;
}
else {
std::cout << "Bulunamadi\n";
}
}Çıktı:
Bulundu: 2 b
Örnek
#include <iostream>
#include <map>
int main()
{
std::multimap<int, char> anahtar {
{1, 'A'},
{2, 'B'},
{2, 'C'},
{2, 'D'},
{4, 'E'},
{3, 'F'}
};
auto ata = anahtar.equal_range(2);
//equal_range():2 olanları ata.
for (auto i = ata.first; i != ata.second; ++i)
{
std::cout << i->first << ": " << i->second << '\n';
}
}Çıktı:
Örnek
#include <iostream>
#include <map>
#include <vector>
using namespace std;
class TelephoneDirectory
{
public:
void add_entry(string name, int number);
int find_entry(string name);
vector<string> find_entries(int number);
void print_all();
private:
map<string, int> database;
multimap<int, string> inverse_database;
};
void TelephoneDirectory::add_entry(string name, int number) //Kisi ekle.
{
database[name] = number;
inverse_database.insert(make_pair(number, name));
}
int TelephoneDirectory::find_entry(string name) //Isme ait numarayi dondurur
{
map<string, int>::iterator p = database.find(name);
if (p == database.end()) // Veri tabaninin sonuna kadar kontrol eder.
return 0; // not found
else
return p->second;
}
vector<string> TelephoneDirectory::find_entries(int number) //Numaraya tanimli kisileri dondurur.
{
multimap<int, string>::iterator lower
= inverse_database.lower_bound(number); //Gonderilen numaraya tanimli ilk kisiye esitler.
multimap<int, string>::iterator upper
= inverse_database.upper_bound(number); //Gonderilen numaraya tanimli son kisiye esitler.
vector<string> result;
for (multimap<int, string>::iterator pos = lower; //Numaraya tanimli kisileri bastirir.
pos != upper; pos++)
result.push_back(pos->second);
return result;
}
void TelephoneDirectory::print_all() //Baslangıctan sona kadar rehberi yazdirir.
{
for (map<string, int>::iterator pos = database.begin();
pos != database.end(); pos++)
{
cout << pos->first << ": " << pos->second << "\n";
}
}
int main()
{
TelephoneDirectory data;
data.add_entry("Fred", 7235591);
data.add_entry("Mary", 3841212);
data.add_entry("Sarah", 3841212);
cout << "Number for Fred: " << data.find_entry("Fred") << "\n";
vector<string> names = data.find_entries(3841212);
cout << "Names for 3841212: ";
for (unsigned int i = 0; i < names.size(); i++)
cout << names[i] << " ";
cout << "\n";
cout << "All names and numbers:\n";
data.print_all();
return 0;
}Çıktı:
Number for Fred: 7235591 Names for 3841212: Mary Sarah All names and numbers: Fred: 7235591 Mary: 3841212 Sarah: 3841212