The C++ set::swap function is used to exchange all elements of one set with all elements of another set. To apply this function, the data-type of both sets must be same, although the size may differ.

### Syntax

```void swap (set& other);
```
```void swap (set& other);
```

### Parameters

 `other` Specify set, whose elements need to be exchanged with another set.

None.

### Time Complexity

Constant i.e, Θ(1)

### Example:

In the below example, the set::swap function is used to exchange all elements of set MySet1 with all elements of set MySet2.

```#include <iostream>
#include <set>
using namespace std;

int main (){
set<int> MySet1{10, 20, 30, 40, 50};
set<int> MySet2{5, 55, 555};

set<int>::iterator it;

cout<<"Before Swapping, The MySet1 contains:";
for(it = MySet1.begin(); it != MySet1.end(); ++it)
cout<<" "<<*it;
cout<<"\nBefore Swapping, The MySet2 contains:";
for(it = MySet2.begin(); it != MySet2.end(); ++it)
cout<<" "<<*it;

MySet1.swap(MySet2);

cout<<"\n\nAfter Swapping, The MySet1 contains:";
for(it = MySet1.begin(); it != MySet1.end(); ++it)
cout<<" "<<*it;
cout<<"\nAfter Swapping, The MySet2 contains:";
for(it = MySet2.begin(); it != MySet2.end(); ++it)
cout<<" "<<*it;

return 0;
}
```

The output of the above code will be:

```Before Swapping, The MySet1 contains: 10 20 30 40 50
Before Swapping, The MySet2 contains: 5 55 555

After Swapping, The MySet1 contains: 5 55 555
After Swapping, The MySet2 contains: 10 20 30 40 50
```