stack swap() in C++ STL

Stacks are a type of container adaptors with LIFO(Last In First Out) type of work, where a new element is added at one end and (top) an element is removed from that end only.

stack::swap()

This function is used to swap the contents of one stack with another stack of same type but the size may vary.

Syntax :



stackname1.swap(stackname2)

Parameters: The name of the stack with which the contents have to be swapped.

Result: All the elements of the 2 stack are swapped.

Examples:

contents of the stack from top to bottom are
Input  : mystack1 = {4, 3, 2, 1}
         mystack2 = {9, 7 ,5, 3}
         mystack1.swap(mystack2);
Output : mystack1 =  9, 7, 5, 3
         mystack2 =  4, 3, 2, 1

Input  : mystack1 = {7, 5, 3, 1}
         mystack2 = {8, 6, 4, 2}
         mystack1.swap(mystack2);
Output : mystack1 =  8, 6, 4, 2
         mystack2 =  7, 5, 3, 1

Note: In stack container, the elements are printed in reverse order because the top is printed first then moving on to other elements.

filter_none

edit
close

play_arrow

link
brightness_4
code

// CPP program to illustrate
// Implementation of swap() function
#include <stack>
#include <iostream>
using namespace std;
  
int main()
{
        // stack container declaration
    stack<int> mystack1;
    stack<int> mystack2;
      
       // pushing elements into first stack
    mystack1.push(1);
    mystack1.push(2);
    mystack1.push(3);
    mystack1.push(4);
      
       // pushing elements into 2nd stack
    mystack2.push(3);
    mystack2.push(5);
    mystack2.push(7);
    mystack2.push(9);
  
        // using swap() function to swap elements of stacks
    mystack1.swap(mystack2);
  
        // printing the first stack
    cout<<"mystack1 = ";
     while (!mystack1.empty()) {
        cout<<mystack1.top()<<" ";
        mystack1.pop();
    }
  
        // printing the second stack
    cout<<endl<<"mystack2 = ";
    while (!mystack2.empty()) {
        cout<<mystack2.top()<<" ";
        mystack2.pop();
    }
    return 0;
}

chevron_right


Output:

mystack1 = 9 7 5 3
mystack2 = 4 3 2 1


My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.



Improved By : terror19_7



Article Tags :
Practice Tags :


3


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.