I. Preface

Computer programs are inseparable from algorithms and data structures. Data structures are a discipline that is produced for computers to store and use data in a more efficient, simple and convenient way. This paper introduces the implementation of stack and queue

Two, diagram

III. linear table

1. Sequential storage structure: the data elements of linear table are successively stored in a storage unit with continuous address
2. Chain storage structure: a set of arbitrary storage units is used to store the data elements of a linear table. This set of storage units can be continuous or discontinuous, and there is no linear relationship between space and memory

Four, stack

Stack

1. Linear tables that can only be inserted and deleted at one end

2. Functions realized

• push: add data at the top level.
• pop: returns and removes the top-level data.
• peek: returns the value of the topmost data, but does not remove it.
• Empty: returns a Boolean value indicating whether the current stack is empty.

2-1. Initialization

private int[] arr;
    //Constant in uppercase
    private final static int SIZE = 1;
    //Current pointer to stack
    private int index;

    //Constructor has no parameters
    public StackDemo() {
        arr = new int[SIZE];
        index = -1;
    }

2-2,push

//Push
private void push(int target){
    if (index == SIZE){
        throw  new  StackOverflowError();
    }else {
        //At the beginning, it's - 1, it needs to be added before
        arr[++index] = target;
    }
}

2-3,peek

//Back to top of stack element
private int peek(){
    if (index == -1){
        throw new StackOverflowError();
    }else {
        return arr[index];
    }
}

2-4,empty

    //Sentence blank
    private boolean empty(){
        if (index == -1){
            return true;
        }
        return false;
    }

3. Code implementation

import java.util.Arrays;

/**
 *
 * @author buer
 * @date 2019/1/20
 */
public class StackDemo {
    private int[] arr;
    //Constant in uppercase
    private final static int SIZE = 1;
    //Current pointer to stack
    private int index;

    //Constructor has no parameters
    public StackDemo() {
        arr = new int[SIZE];
        index = -1;
    }

    //Push
    private void push(int target){
        if (index == SIZE){
            throw  new  StackOverflowError();
        }else {
            //At the beginning, it's - 1, it needs to be added before
            arr[++index] = target;
        }
    }

    //Stack out
    private int pop(){
        if (index == -1){
            throw new StackOverflowError();
        }else {
            return arr[index--];
        }
    }

    //Back to top of stack element
    private int peek(){
        if (index == -1){
            throw new StackOverflowError();
        }else {
            return arr[index];
        }
    }

    //Sentence blank
    private boolean empty(){
        if (index == -1){
            return true;
        }
        return false;
    }
    public static void main(String[] args) {
        StackDemo stackDemo = new StackDemo();
        stackDemo.push(1);
        System.out.println(stackDemo.toString());
        stackDemo.pop();
        System.out.println(stackDemo.toString());

    }

    @Override
    public String toString() {
        return "StackDemo{" +
                "arr=" + Arrays.toString(arr) +
                ", index=" + index +
                '}';
    }
}

application

1. Bracket matching

2. Infix expression (human thinking) and suffix expression (computer calculation)

3, recursion

4. Browser forward and backward function

Reference material

https://zh.wikipedia.org
https://www.zhihu.com/question/21318658
http://www.ruanyifeng.com/blog/2013/11/stack.html