Tuples in C++

Last Updated : 8 Jan, 2025

A tuple is an object that can hold a number of elements. The elements can be of different data types. The elements of tuples are initialized as arguments in order in which they will be accessed. Tuples are a versatile data structure for grouping values. To understand how to use tuples in C++ and their applications, the C++ Course provides comprehensive tutorials and examples.

Operations on Tuple

1. get(): get() is used to access the tuple values and modify them, it accepts the index and tuple name as arguments to access a particular tuple element.

2. make_tuple(): make_tuple() is used to assign tuple with values. The values passed should be in order with the values declared in tuple.

CPP

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

int main() {
  
    // Declaring tuple
    tuple<char, int, float> geek;

    // Assigning values to tuple using make_tuple()
    geek = make_tuple('a', 10, 15.5);

    // Printing initial tuple values using get()
    cout << "The initial values of tuple are: ";
    cout << get<0>(geek) << " " << get<1>(geek);
    cout << " " << get<2>(geek) << endl;

    // Use of get() to change values of tuple
    get<0>(geek) = 'b';
    get<2>(geek) = 20.5;

    // Printing modified tuple values
    cout << "The modified values of tuple are: ";
    cout << get<0>(geek) << " " << get<1>(geek);
    cout << " " << get<2>(geek) << endl;

    return 0;
}

Output

The initial values of tuple are: a 10 15.5
The modified values of tuple are: b 10 20.5

Explanation: In the above code, get() modifies the 1st and 3rd value of tuple.

3. tuple_size: It returns the number of elements present in the tuple.

CPP

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

int main() {
  
    // Initializing tuple
    tuple<char, int, float> geek(20, 'g', 17.5);

    // Use of size to find tuple_size of tuple
    cout << "The size of tuple is: ";
    cout << tuple_size<decltype(geek)>::value;

    return 0;
}

Output

The size of tuple is: 3

4. swap(): The swap(), swaps the elements of the two different tuples.

CPP

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

int main() {
  
    // Initializing 1st tuple
    tuple<int, char, float> tup1(20, 'g', 17.5);

    // Initializing 2nd tuple
    tuple<int, char, float> tup2(10, 'f', 15.5);

    // Printing 1st and 2nd tuple before swapping
    cout << "The first tuple elements before swapping are: ";
    cout << get<0>(tup1) << " " << get<1>(tup1) << " " << get<2>(tup1) << endl;
    cout << "The second tuple elements before swapping are: ";
    cout << get<0>(tup2) << " " << get<1>(tup2) << " " << get<2>(tup2) << endl;

    // Swapping tup1 values with tup2
    tup1.swap(tup2);

    // Printing 1st and 2nd tuple after swapping
    cout << "The first tuple elements after swapping are: ";
    cout << get<0>(tup1) << " " << get<1>(tup1) << " " << get<2>(tup1) << endl;
    cout << "The second tuple elements after swapping are: ";
    cout << get<0>(tup2) << " " << get<1>(tup2) << " " << get<2>(tup2) << endl;

    return 0;
}

Output

The first tuple elements before swapping are: 20 g 17.5
The second tuple elements before swapping are: 10 f 15.5
The first tuple elements after swapping are: 10 f 15.5
The second tuple elements after swapping are: 20 g 17.5

5. tie(): The work of tie() is to unpack the tuple values into separate variables. There are two variants of tie(), with and without "ignore" , the "ignore" ignores a particular tuple element and stops it from getting unpacked.

CPP

#include <iostream>
#include <tuple> // for tie() and tuple
using namespace std;

int main() {   
    // Initializing variables for unpacking
    int i_val;
    char ch_val;
    float f_val;   
    
    // Initializing tuple
    tuple<int, char, float> tup1(20, 'g', 17.5);

    // Use of tie() without ignore
    tie(i_val, ch_val, f_val) = tup1;
    
    // Displaying unpacked tuple elements without ignore
    cout << "The unpacked tuple values (without ignore) are: ";
    cout << i_val << " " << ch_val << " " << f_val;
    cout << endl;
    
    // Use of tie() with ignore
    // ignores char value
    tie(i_val, ignore, f_val) = tup1;
    
    // Displaying unpacked tuple elements with ignore
    cout << "The unpacked tuple values (with ignore) are: ";
    cout << i_val << " " << f_val;
    cout << endl;

    return 0;
}

Output

The unpacked tuple values (without ignore) are: 20 g 17.5
The unpacked tuple values (with ignore) are: 20 17.5

6. tuple_cat(): This function concatenates two tuples and returns a new tuple.

CPP

#include <iostream>
#include <tuple> // for tuple_cat() and tuple
using namespace std;

int main() {
    // Initializing 1st tuple
    tuple<int, char, float> tup1(20, 'g', 17.5);

    // Initializing 2nd tuple
    tuple<int, char, float> tup2(30, 'f', 10.5);
    
    // Concatenating 2 tuples to return a new tuple
    auto tup3 = tuple_cat(tup1, tup2);
    
    // Displaying new tuple elements
    cout << "The new tuple elements in order are: ";
    cout << get<0>(tup3) << " " << get<1>(tup3) << " " 
         << get<2>(tup3) << " " << get<3>(tup3) << " " 
         << get<4>(tup3) << " " << get<5>(tup3) << endl;

    return 0;
}

Output

The new tuple elements in order are: 20 g 17.5 30 f 10.5

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