C++ pop()

Introduction to C++ pop()

C++ pop() method is part of the C++ stack data structure which is basically used for removing the topmost element of the stack. This pop() method in stack acts as a deletion operation. Deletion operation in stack is performed in Last in first out fashion i.e. LIFO order. Deletion in stack is always performed from top of the stack which signifies that the element which is inserted first will be considered as an element to be deleted first from the entire stack. Logically if the element inserted in the last is the element to be deleted first from the stack then the stack size gets decreased in size by 1.

Syntax

The syntax flow of the C++ pop() is as follows :

Name_of_Stack.pop()

• Name_of_stack: This represents the stack where the elements are present in an order.
• Pop: It is the method name which is called to decrease the size of the stack by one as the entire stack is arranged with the elements.

Parameter: The function don’t consider any of the parameters into consideration rather it just deleted the last element present in the stack and makes the size of the stack decreased by one as the last element is the first element to get deleted.

There is no return value for the C++ pop() function as it is used just for removal of elements from the stack with a fashion where the last element is the first element to get removed from the stack. Therefore, the return type of the function is null.

How pop() method works in C++?

• pop() method is a method as part of the stack data structure whose main aim is to remove the topmost element from the stack in some fashion. The element gets removed from the stack container and due to removal of that element the stack size gets decreased by one. The complexity of  pop() method is also constant as there is no major change that is performed on the stack data structure except for the fact of removing element from top of stack.
• Even the element removal happens from the top of the stack which does not provide more changes in the values of the stack. The modification of elements within the stack do not make much difference but it does performs very minute difference like it performs the deletion operation which is used for reflecting the change at the top of the stack with the element i.e. it changes the topmost position of the element of stack by reflecting  the top position of the stack but the element within the stack gets decreased by the size of one.
• It can be considered and said that the Last in first out fashion of element removal gels well with the pop() method. Pop() method in C++ also falls for some error and exception like it will give error if the value which is passed as an argument from the method, although it is not a conventional way of making the function fed with arguments if this is performed then it will definitely throw an error.
• Also, sometimes it is not guaranteed for the fact that there will be some exceptions or if the parameter will throw some exception with the values for the method. Stack push and stack pop are two completely opposite methods which supports for the stack as a data structure but then the entire pop() function which deals with Last in first out order do not support for the stack push method which follows for FIFO(First in First out method).
• Mostly the return type for the pop() method is void as it doesn’t perform any critical function rather it performs only the function relevant to the stack for removing the topmost element from the stack. It is a convention that by default all the action related to the pop() method will be applied on top of the stack. There are some advantages associated with the pop() method of  elements which is like the unwanted element present within stack gets removed with some manipulation and deletion operation thus making overall size of the stack maintained with some required number of elements.
• Also, complexity of element retrieval is not that much because it just removes elements from the stack rather making entire set of elements in stack merged with unwanted elements as well. There is not much difference in terms of complexity for the pop() method as a function because it just makes changes and manipulation on top of the element .

Examples to Implement C++ pop()

Below are the examples mentioned :

Example #1

This program demonstrates the usage of C++ pop() method which removes the topmost element from the stack as shown in the output.

Code:

#include <iostream>
#include <stack>
int main()
{
std::stack<int> n_stck;
for(int h=0; h<6; h++)
n_stck.push(h);
std::cout <<"Pop_Out_Elements : ";
while (!n_stck.empty () )
{
std::cout <<" " << n_stck.top();
n_stck.pop();
}
std::cout<<"\n";
return 0;
}

Output:

Example #2

This program demonstrates the C++ pop() method where the top elements get removed from the stack as shown in the output.

Code:

#include <iostream>
#include <stack>
using namespace std;
int main()
{
stack<int> m_stck;
m_stck.push(5);
m_stck.push(8);
m_stck.push(7);
m_stck.push(2);
m_stck.push(11);
m_stck.push(10);
m_stck.pop();
m_stck.pop();
m_stck.pop();
while (!m_stck.empty()) {
cout << ' ' << m_stck.top();
m_stck.pop();
}
}

Output:

Example #3

This program demonstrates the C++ pop() and push() both function as part of the standard library function which is used for removing the elements from the stack as shown in the output.

Code:

#include <iostream>
#include <stack>
using namespace std;
int main()
{
int p = 0;
stack<int> m_stck;
m_stck.push(12);
m_stck.push(10);
m_stck.push(3);
m_stck.push(1);
m_stck.push(9);
m_stck.push(14);
while (!m_stck.empty()) {
m_stck.pop();
p++;
}
cout << p;
}

Output:

Conclusion

C++ pop() method is part of the stack data structure which contains the method in the standard library of stack and lets programmer use these functionalities with ease and flexibility. This provides the programmers an insight about the content and data of the stack which helps in maintaining the proper and appropriate elements by removing the unessential elements from the stack.

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