C++ Utility Library - swap Function


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Description

It exchanges the values of a and b.

Declaration

Following is the declaration for std::swap function.

template <class T> void swap (T& a, T& b);

C++11

template <class T> void swap (T& a, T& b)
   noexcept (is_nothrow_move_constructible<T>::value && is_nothrow_move_assignable<T>::value);

Parameters

a, b − These are two objects.

Return Value

none

Exceptions

Basic guarantee − if the construction or assignment of type T throws.

Data races

Both a and b are modified.

Example

In below example explains about std::swap function.

#include <iostream>
#include <utility>

int main () {

   int foo[4];
   int bar[] = {100,200,300,400};
   std::swap(foo,bar);

   std::cout << "foo contains:";
   for (int i: foo) std::cout << ' ' << i;
   std::cout << '\n';

   return 0;
}

Let us compile and run the above program, this will produce the following result −

foo contains: 100 200 300 400
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