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std::stack<T,Container>::top - cppreference.com

From cppreference.com

reference top();

 (1)

const_reference top() const;

 (2)

Returns reference to the top element in the stack. This is the most recently pushed element. This element will be removed on a call to pop(). Equivalent to: c.back().

Parameters

(none)

Return value

Reference to the last element.

Complexity

Constant.

Example

#include <iostream>
#include <stack>

void reportStackSize(const std::stack<int>& s)
{
    std::cout << s.size() << " elements on stack\n";
}

void reportStackTop(const std::stack<int>& s)
{
    // Leaves element on stack
    std::cout << "Top element: " << s.top() << '\n';
}
 
int main()
{
    std::stack<int> s;
    s.push(2);
    s.push(6);
    s.push(51);
    
    reportStackSize(s);
    reportStackTop(s);
    
    reportStackSize(s);
    s.pop();
    
    reportStackSize(s);
    reportStackTop(s);
}

Output: 

3 elements on stack
Top element: 51
3 elements on stack
2 elements on stack
Top element: 6

See also

inserts element at the top
(public member function) [edit]
removes the top element
(public member function) [edit]