What is a stack in java

Heap, stack and data structure in the system Heap and stack are not the same concept. It can be said that the heap and stack in the system are real physical memory areas, and the heap and stack in the data structure are abstract data storage structures.

Stack: actually satisfies the last-in-first-out property. It is a data structure in which data items are arranged in order, and can only be placed at one end ( Called the top of the stack (top), data items are inserted and deleted. (Recommended learning: java course)

Stack area (stack)—is automatically allocated and released by the compiler to store functions Parameter values, values ​​of local variables, etc. It operates like a stack in a data structure.

The advantage of the stack is that the access speed is faster than the heap, second only to the registers directly located in the CPU. But the disadvantage is that the size and lifetime of the data stored in the stack must be determined and there is a lack of flexibility.

Code:

Stack的基本使用
初始化
Stack stack=new Stack
判断是否为空
stack.empty()
取栈顶值（不出栈）
stack.peek()
进栈
stack.push(Object);
出栈
stack.pop();
 
实例：
public class Test01 {
    public static void main(String[] args) {
        Stack stack=new Stack();
        //1.empty()栈是否为空
        System.out.println(stack.empty());
        //2.peek()栈顶值    3.进栈push()
        stack.push(new Integer(1));
        stack.push("b");
        System.out.println(stack.peek());
        //4.pop()出栈
        stack.pop();
        System.out.println(stack.peek());
        
    }
}

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