Pair
Pair in C++ STL is used to combine two values having different or same data types. It provides a way to store two different values as a single element. The individual values of a pair can be accessed through its public members first and second.
To use STL built-in pair, you need to include <utility> header.
Code Implementation
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 | //// main.cpp// Pair//// Created by Himanshu on 11/04/22.//#include <iostream>#include <utility>#include <vector>#include <string>using namespace std; int main () { //Initializations //using make_pair pair<int, int> pairRank = make_pair(1, 98); //using value init pair<int, string> pairNameFirst (1, "Anon"); //using copy constructor pair<int, string> pairTemp(pairNameFirst); cout<<"pairRank values:"<<endl; cout<<pairRank.first<<", "<<pairRank.second<<endl; //accessing pair elements using method get<> cout<<"pairNameFirst values:"<<endl; cout<<get<0>(pairNameFirst)<<", "<<get<1>(pairNameFirst)<<endl<<endl; vector<pair<int, int>> pairRankVector; vector<pair<int, string>> pairNameVector; vector<pair<int, int>>::iterator rankItr; vector<pair<int, string>>::iterator nameItr; pairRankVector.push_back(pairRank); pairNameVector.push_back(pairNameFirst); vector<int> rankMarks = {95, 90, 87, 83, 75}; vector<string> rankNames = {"Bruw", "Cync", "Droke", "Elph", "Frel"}; int n = (int) rankMarks.size(); for (int i=0; i<n; i++) { pairRankVector.push_back(make_pair(i+2, rankMarks[i])); pairNameVector.push_back(make_pair(i+2, rankNames[i])); } cout<<"Size of pairRankVector: "<<pairRankVector.size()<<endl<<endl; //accessing vector elements using iterator, //accessing pair elements using -> operator //accessing vector element using (*iterator) for (rankItr = pairRankVector.begin(), nameItr = pairNameVector.begin(); rankItr != pairRankVector.end(); rankItr++, nameItr++) { cout<<rankItr->first<<" "<<nameItr->second<<" "<<(*rankItr).second<<endl; } return 0;} |
Output
pairRank values: 1, 98 pairNameFirst values: 1, Anon Size of pairRankVector: 6 1 Anon 98 2 Bruw 95 3 Cync 90 4 Droke 87 5 Elph 83 6 Frel 75
Here’s a working example: Pair
Tuple
Tuple unlike pair can be used to combine two or more than two values having different or same data types.
To use STL built-in tuple, you need to include <tuple> header.
Code Implementation
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 | //// main.cpp// Tuple//// Created by Himanshu on 11/04/22.//#include <iostream>#include <tuple>#include <vector>#include <string>using namespace std; int main () { //Initializations //using make_tuple tuple<int, string, int> tupleFirst = make_tuple(1, "Anon", 98); //using value init tuple<int, string, int> tupleLast (7, "Glee", 67); //using copy constructor tuple<int, string, int> tupleTemp(tupleLast); cout<<"tupleTemp values:"<<endl; cout<<get<0>(tupleTemp)<<", "<<get<1>(tupleTemp)<<", "<<get<2>(tupleTemp)<<endl<<endl; vector<int> rankMarks = {95, 90, 87, 83, 75}; vector<string> rankNames = {"Bruw", "Cync", "Droke", "Elph", "Frel"}; vector<tuple<int, string, int>> nameList; nameList.push_back(tupleFirst); int n = (int) rankMarks.size(); for (int i=0; i<n; i++) { nameList.push_back(make_tuple(i+2, rankNames[i], rankMarks[i])); } nameList.push_back(tupleLast); cout<<"Size of (vector) nameList: "<<nameList.size()<<endl<<endl; for (tuple<int, string, int> t: nameList) { cout<<get<0>(t)<<" "<<get<1>(t)<<" "<<get<2>(t)<<endl; } return 0;} |
Output
tupleTemp values: 7, Glee, 67 Size of (vector) nameList: 7 1 Anon 98 2 Bruw 95 3 Cync 90 4 Droke 87 5 Elph 83 6 Frel 75 7 Glee 67
Here’s a working example: Tuple