C++ Stack push function is used for adding new elements at the top of the stack. If we have an array of type stack and by using the push function we can insert new elements in the stack. The elements are inserted at the top of the stack. The element which is inserted most initially is deleted at the end and vice versa as stacks follow LIFO principle.
Syntax
void push (const value_type& value);
Parameters
value : The parameter represents the value to which the element is initialized. The parameter specifies the value of the newly inserted element. The element 'val' becomes the new top element of the stack after function execution.
Return value
The function only inserts element and does not return any value. The return type of the function can be thought as void.
Example 1
//The program is used to demonstrate the use of the push function of the stack by insertion of simple integer values.
#include <iostream>
#include <stack>
int main()
{
std::stack<int> newstack;
for(int j= 0; j<5; j++)
newstack.push(j);
std::cout << "Poping the elements out of the stack??.";
while (!newstack.empty () )
{
std::cout<<" " << newstack.top ();
newstack.pop();
}
std::cout<<"\n";
return 0;
}
Output:
Poping the elements out of the stack..... 4 3 2 1 0
Example 2
#include <iostream>
#include <stack>
int main()
{
std::stack<int> newstack;
newstack.push(69);
newstack.push(79);
newstack.push(80);
while (!newstack.empty())
{
std::cout<<" " << newstack.top ();
newstack.pop();
}
return 0;
}
Output:
90 85 80 79 69
Example 3
//The program is used to demonstrate the use of the push function of the stack by insertion of simple integer values.
#include <iostream>
#include <stack>
int main()
{
std::stack<int> newstack;
newstack.push(11);
newstack.push(22);
newstack.push(33);
newstack.push(44);
std::cout << "Popping out elements?";
newstack.pop();
newstack.pop();
while (!newstack.empty () )
{
std::cout << " " << newstack.top();
newstack.pop();
}
std:: cout<<'\n';
return 0;
}
Output:
Popping out elements... 22 11
Example 4
//The program is used to demonstrate the use of the push function of the stack by insertion of simple integer values.
#include <iostream>
#include <stack>
int main()
{
std::stack<int> a,b;
a.push(5); a.push(8); a.push(50);
b.push(132); b.push(45);
std::cout<<"Size of a: "<<a.size();
std::cout<<"\n Size of b:" <<b.size();
return 0;
}
Output:
Size of a: 3
Size of b:2
Complexity
One call is made to the push back on the container that is underlying, which is necessary for the insertion operation on the element to get completed.
Data races
The modification is made to the container, and the elements contained. The addition of a new element modifies all the underlying stack elements.
Exception Safety
Guarantee as equivalent to the operations that are performed on the underlying container object is provided.