pair, tuple, and Structured Binding in C++

The C++ Standard Library provides pair and tuple for storing multiple values within a single structure. With C++17, structured binding was introduced, offering a cleaner and more readable way to unpack these structures into separate variables. This article explains pair, tuple, and structured binding in detail with practical examples.

1) What is pair?

std::pair is a simple data structure that holds two values, which may be of different types. Pairs are widely used in functions that return two values.

• Contains two elements: first and second
• Each element can have a different type
• Useful for returning multiple values from functions

#include <utility>
#include <iostream>
using namespace std;

int main() {
    pair<string, int> person("Ali", 30);

    cout << person.first << ", " << person.second << endl;
}

Output: Ali, 30

2) Using make_pair

auto p = make_pair("Ayse", 25);
cout << p.first << ", " << p.second;

3) Function Returning a pair

pair<int,int> getMinMax(int a, int b) {
    return { min(a, b), max(a, b) };
}

int main() {
    auto result = getMinMax(15, 40);
    cout << "Min: " << result.first 
         << ", Max: " << result.second;
}

4) What is tuple?

std::tuple is a generalized version of pair and can store more than two values, even if they are of different types. It is ideal for grouping heterogeneous values.

#include <tuple>
#include <iostream>
using namespace std;

int main() {
    tuple<string, int, double> student("Mehmet", 22, 3.40);

    cout << get<0>(student) << endl;
    cout << get<1>(student) << endl;
    cout << get<2>(student) << endl;
}

5) Using make_tuple

auto data = make_tuple("Book", 350, 49.90);

cout << get<0>(data) << endl;
cout << get<1>(data) << endl;
cout << get<2>(data) << endl;

6) tuple Size and Type Information

tuple<string, int, double> t;

cout << tuple_size<decltype(t)>::value << endl;
// tuple size = 3

// Extracting type information
using T0 = tuple_element<0, decltype(t)>::type;

7) Structured Binding (C++17)

Structured binding provides a clearer and more readable way to unpack tuple or pair values into individual variables.

auto student = make_tuple("Zeynep", 21, 3.75);

auto [name, age, gpa] = student;

cout << name << " - " << age << " - " << gpa;

8) Structured Binding with pair

pair<string, int> book("C++", 450);

auto [title, pages] = book;

cout << title << " - " << pages;

9) Returning a tuple from a Function

tuple<string,double,int> getProduct() {
    return { "Laptop", 14500.99, 24 };
}

int main() {
    auto [name, price, stock] = getProduct();

    cout << name << ", " 
         << price << ", " 
         << stock;
}

10) Practical Example — User Info

#include <tuple>
#include <iostream>
using namespace std;

tuple<string,int,string> getUser() {
    return { "Ahmet", 28, "Engineer" };
}

int main() {
    auto [name, age, job] = getUser();

    cout << name << " (" << age << ") - " << job;
}

11) When Should You Use Each?

• pair: When you only need to store two values.
• tuple: When you need to store more than two values of different types.
• structured binding: When you want clean and readable unpacking.

pair → simple two-value structure
tuple → multiple, heterogeneous values
structured binding → clean, readable extraction

12) TL;DR

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