原文链接：https://blog.csdn.net/qq_39355828/article/details/117414362 (opens new window)

Java简单实现计算器——用数组实现栈

参考尚硅谷 数据结构视频

package DataStructures.stack;

import java.util.Scanner;

class ArrayStack2
{
    private int maxSize;//栈的容量
    private int[] stack;
    private int top=-1;
    public ArrayStack2(int maxSize)//初始化栈的大小
    {
        this.maxSize=maxSize;
        stack=new int[this.maxSize];
    }
    public boolean Full()//判断是否栈满
    {
        return top==maxSize-1;
    }
    public boolean Empty()
    {
        return top==-1;
    }
    //入栈
    public void push(int value)
    {
        if(Full()) {
            System.out.println("The stack is full!");
            return;
        }
        top++;
        stack[top]=value;
    }
    //出栈
    public int pop()
    {
        if(Empty())
        {
            System.out.println("The stack is empty!");
            return 0;
        }
        int temp=stack[top];
        top--;
        return temp;
    }
    //遍历栈
    public void displayStack()
    {
        if(Empty())
            System.out.println("The stack is empty!");
        int temp=top;
        for(int i=0;i<=temp;i++)
        {
            System.out.printf("stack[%d] %d\n",i,stack[i]);
            System.out.println("  ");
        }
    }
//返回栈顶
    public int peek()
    {
        return stack[top];
    }
    public int priority(char oper)
    {
        if(oper=='*'||oper=='/')//优先级比较高的操作符
        {
            return 1;
        }
        else if(oper=='+'||oper=='-')//优先级比较低的操作符
            return 0;
        else
            return -1;
    }
    //判断是不是一个运算符
    public boolean ioOrder(char val)
    {
        return val=='+'||val=='-'||val=='*'||val=='/';
    }
    //计算方法
    public int cal(int num1,int num2,int oper)
    {
        int res=0;
        switch(oper)
        {
            case'+':
                res=num1+num2;
                break;
            case'-':
                res=num2-num1;
                break;
            case'*':
                res=num1*num2;
                break;
            case'/':
                res=num2/num1;
                break;
            default:
                break;
        }
        return res;
    }

}
public class Calculator {
    public static void main(String[] args) {
        String exp="3+2*6-2";
        //创建两个栈，数栈，一个符号栈
        ArrayStack2 numStack=new ArrayStack2(10);
        ArrayStack2 operStack=new ArrayStack2(10);
        int index=0;//用于扫描
        int num1=0;
        int num2=0;
        int oper=0;
        int res=0;
        char ch=' ';
        while(true)
        {
            ch=exp.substring(index,index+1).charAt(0);
            System.out.println(ch);
            //判断ch是什么
            if(operStack.ioOrder(ch))
            {
                if(!operStack.Empty())
                {
                    //如果符号栈中有运算符 要比较
                    if(operStack.priority(ch)<=operStack.priority((char) operStack.peek()))
                    {
                        num1=numStack.pop();
                        num2=numStack.pop();
                        oper=operStack.pop();
                        res=numStack.cal(num1,num2,oper);
                        //运算结果加入数栈
                        numStack.push(res);
                        operStack.push(ch);
                    }
                    else
                    {
                        operStack.push(ch);
                    }
                }
                else
                {
                    operStack.push(ch);
                }
            }
            else
                numStack.push(ch-48);
            //判断是否扫描到最后
            index++;
            if(index>=exp.length())
            {
                break;
            }
        }
        while (true)//符号栈为空，数栈中只有一个数值
        {
            if(operStack.Empty())
                break;
            num1=numStack.pop();
            num2=numStack.pop();
            oper=operStack.pop();
            res=numStack.cal(num1,num2,oper);
            numStack.push(res);
        }
        System.out.printf("表达式结果%s =%d ",exp,numStack.pop());

    }
}