C++ STL (5): stack container

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1 Basic concepts of stack

Features : The stack stackis a first-in -last-out ( FILOFirst In Last Out) data structure, and only the top end of the stack can insert or delete data.

Stack top element :, only the top element top()in the stack can be accessed and used by the outside world, soStack does not allow traversal behavior.
Push/Push the stack :, push()push the element to the top of the stack. Pop
/pop the stack :, pop()pop the element from the top of the stack.

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2 Stack common interface

Note: When using the stack container, you need to include the header file #include <stack>.

Constructor :
① stack<T> stk;: Default no-argument constructor, implemented by class template .
② stack(const stack &stk);: Copy constructor, use the existing stack object to initialize a new object.

Assignment operation ::
stack& operator=(const stack &stk);Overload the assignment operator, use the target stack container to assign a value to the current stack container.

Data access ::
push(elem);Push elements to the top of the stack.
pop();: Pop the element from the top of the stack.
top();: Return to the top element of the stack.

Size operation :
empty();Judge whether the stack is empty.
size();: Return the size of the stack.

Example : Common interfaces of the stack

#include <iostream>
using namespace std;
#include <stack>

int main() {
    
    
	//创建stack容器
	stack<int> s;

	//压栈
	s.push(1);
	s.push(2);
	s.push(3);
	s.push(4);
	s.push(5);

	cout << "当前栈的大小：" << s.size() << endl;	//5

	while (!s.empty()) {
    
    
		cout << "当前栈顶元素：" << s.top() << endl;	//5→4→3→2→1

		//出栈
		s.pop();
	}
	cout << "当前栈的大小：" << s.size() << endl;	//0

	return 0;
}