C++ queue - swap() Function
The C++ queue swap() function is used to exchange all elements of one queue with all elements of another queue. To apply this function, the data-type of both queues must be same, although the size may differ.
Syntax
template <class T, class Container>
void swap (queue<T,Container>& lhs,
queue<T,Container>& rhs)
noexcept(noexcept(lhs.swap(rhs)));
Parameters
lhs |
First queue. |
rhs |
Second queue. |
Return Value
None.
Time Complexity
Constant i.e, Θ(1).
Example:
In the example below, the swap() function is used to exchange all elements of queue que1 with all elements of queue que2.
#include <iostream>
#include <queue>
using namespace std;
int main (){
queue<int> que1, que2;
//add new elements in the que1
que1.push(10);
que1.push(20);
que1.push(30);
que1.push(40);
que1.push(50);
//add new elements in the que2
que2.push(5);
que2.push(55);
que2.push(555);
swap(que1, que2);
cout<<"After Swapping, The que1 contains:";
while (!que1.empty()) {
cout<<" "<<que1.front();
que1.pop();
}
cout<<"\nAfter Swapping, The que2 contains:";
while (!que2.empty()) {
cout<<" "<<que2.front();
que2.pop();
}
return 0;
}
The output of the above code will be:
After Swapping, The que1 contains: 5 55 555 After Swapping, The que2 contains: 10 20 30 40 50
❮ C++ <queue> Library
