C++ std::array::swap

The std::array::swap function exchanges the contents of two arrays of the same type and size. It is a simple and efficient way to swap data between arrays without copying elements individually.

Syntax of std::array::swap

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void swap(array& other) noexcept(noexcept(swap(declval<T>(), declval<T>())));

Parameters

ParameterDescription
otherA reference to another array of the same type and size whose contents will be swapped with the current array.

Return Value

The std::array::swap function does not return any value. It swaps the contents of the two arrays in place.

Exceptions

The std::array::swap function does not throw exceptions unless the swap operation for the element type T throws an exception. If T‘s swap is noexcept, the array swap operation is also noexcept.

Examples for std::array::swap

Example 1: Swapping Two Arrays

This example demonstrates how to use swap to exchange the contents of two std::array objects:

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#include <iostream>
#include <array>

int main() {
    std::array<int, 5> arr1 = {1, 2, 3, 4, 5};
    std::array<int, 5> arr2 = {10, 20, 30, 40, 50};

    std::cout << "Before swap:" << std::endl;
    std::cout << "arr1: ";
    for (const auto& elem : arr1) std::cout << elem << " ";
    std::cout << "\narr2: ";
    for (const auto& elem : arr2) std::cout << elem << " ";
    std::cout << std::endl;

    arr1.swap(arr2); // Swap contents of arr1 and arr2

    std::cout << "\nAfter swap:" << std::endl;
    std::cout << "arr1: ";
    for (const auto& elem : arr1) std::cout << elem << " ";
    std::cout << "\narr2: ";
    for (const auto& elem : arr2) std::cout << elem << " ";
    std::cout << std::endl;

    return 0;
}

Explanation:

  1. Two arrays, arr1 and arr2, are initialized with different values.
  2. The contents of both arrays are printed before calling swap.
  3. The swap function exchanges the contents of arr1 and arr2.
  4. The contents of both arrays are printed again to confirm the swap operation.

Output:

Before swap:
arr1: 1 2 3 4 5 
arr2: 10 20 30 40 50 

After swap:
arr1: 10 20 30 40 50 
arr2: 1 2 3 4 5

Example 2: Using std::array::swap with Strings

This example demonstrates swapping the contents of two std::array objects containing strings:

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#include <iostream>
#include <array>
#include <string>

int main() {
    std::array<std::string, 3> arr1 = {"Apple", "Banana", "Cherry"};
    std::array<std::string, 3> arr2 = {"X", "Y", "Z"};

    std::cout << "Before swap:" << std::endl;
    std::cout << "arr1: ";
    for (const auto& elem : arr1) std::cout << elem << " ";
    std::cout << "\narr2: ";
    for (const auto& elem : arr2) std::cout << elem << " ";
    std::cout << std::endl;

    arr1.swap(arr2); // Swap contents of arr1 and arr2

    std::cout << "\nAfter swap:" << std::endl;
    std::cout << "arr1: ";
    for (const auto& elem : arr1) std::cout << elem << " ";
    std::cout << "\narr2: ";
    for (const auto& elem : arr2) std::cout << elem << " ";
    std::cout << std::endl;

    return 0;
}

Explanation:

  1. Two std::array objects containing strings are initialized with different values.
  2. The contents of both arrays are printed before calling swap.
  3. The swap function exchanges the contents of the two arrays.
  4. The contents of both arrays are printed again to confirm the swap operation.

Output:

Before swap:
arr1: Apple Banana Cherry 
arr2: X Y Z 

After swap:
arr1: X Y Z 
arr2: Apple Banana Cherry