(
     )
     del
     C
    
    

     7
     8
     9
     ÷
    
    

     4
     5
     6
     x
    
    

     1
     2
     3
     -
    
    

     0
     .
     =
     +
    
   
  
 

/*
 * @Author: CSU_XZY
 * @Date: 2020-10-15 21:17:45
 * @LastEditors: CSU_XZY
 * @LastEditTime: 2020-10-17 00:04:41
 * @FilePath: \第二天\计算器\compute.js
 * @Description: just to play
 */
var ysf = ['+','÷','=',')','%','x','-','D'];
var sizeyunsuan = ['+','÷','(','x','-'];
var isNumber = ['1','2','3','4','5','6','7','8','9','0','.'];


function showDetails(number)
{
 var number = number.getAttribute("data-value");
 var text = document.getElementById('display').innerText;
//回退一个文字
 if(number === 'D')
 {
  text = text.substring(0,text.length-1);
  document.getElementById('display').innerHTML=text;
  return;
 }
//判断第一个数字是不是运算符
 else if(judgeBegin(number) && text == "")
 return;
//判断是否是连续两个运算符一起输入
 else if(judgeBegin(number) && judgeNext(text,number) && text[text.length-1] !== ')')
 return;
//判断第一个输入是不是‘.'，如果是变为0.
 else if(number === '.' && text == "")
 number = "0.";
//如果输入归0，清空输入
 else if(number === 'C')
 {
  document.getElementById('text').innerHTML="";
  document.getElementById('display').innerHTML="";
  return;
 }
//输入是等号就判断
 else if(number === '=')
 {
  //将数字与运算符分开
  let array = [];
  let n = text.length;
  for(let i = 0; i < n; i++)
  {
   var JudgeNumber = true;
   let res = "";
   //判断第一个数字是否是负号
   if(i===0 && text[i] === '-')
   {
    res+=text[i];
    i++;
   }
   //判断是不是在运算符之后的减号，是就变为负号
   if(i !== 0 && near(array[array.length-1]) && text[i] === '-')
   {
    res+=text[i];
    i++;
   }
   //判断是否为连续的数字
   while(JudgeIsNumber(text[i]) && i < n)
   {
    res += text[i];
    i++;
    JudgeNumber = false;
   }
   //如果不为数字了要回退一个
   if(JudgeNumber === false)
   i--;
   //判断其他运算符
   if(JudgeNumber === true)
   if(judgeBegin(text[i]) || text[i] === '(' || text[i] === '-' || text[i] === ')')
   res+=text[i];
   array.push(res);
  }
  //
   console.log(array);
  //中缀表达式变为后缀表达式
  var hz = houZhui(array);
  console.log(hz);
  var result = compute(hz);
  document.getElementById('text').innerHTML = text;
  document.getElementById('display').innerHTML = result;
  return;
 }
 text+=number;
 document.getElementById('display').innerHTML=text;
}

//判断是不是运算符
function judgeBegin(number)
{
 for(let i = 0; i < ysf.length; i++)
 {
  if(ysf[i] === '-')
  continue;
  if(ysf[i] === number)
  return true;
 }
 return false;
}

//判断是否输入两个连续的运算符
function judgeNext(text,number)
{
 if(number === '-')
 return;
 let a = text.length;
 if(judgeBegin(text[a-1]) && judgeBegin(number))
 return true;
 return false;
}

//判断输入的字符里面是不是数字
function JudgeIsNumber(number){
 for(let i = 0; i < isNumber.length; i++)
 {
  if(isNumber[i] === number)
  return true;
 }
 return false;
}

//判断减号前面是否有别的运算符从而确定是不是负号
function near(number)
{
 for(let i = 0; i < sizeyunsuan.length; i++)
 {
  if(sizeyunsuan[i] === number)
  return true;
 }
 return false;
}

//中缀表达式改为后缀表达式
function houZhui(array)
{
 var stack = [];
 var textArea = [];
 for(let i = 0; i < array.length; i++)
 {
  if(near(array[i]) || array[i] === ')')
  {
   //如果是空直接入栈
   if(stack.length === 0)
   stack.push(array[i]);
   //如果栈顶为左括号直接入栈
   else if(stack[stack.length-1] === '(' && array[i] !== ')')
   stack.push(array[i]);
   //如果输入左括号直接入栈
   else if(array[i] === '(')
   stack.push(array[i]);
   //如果输入的是右括号
   else if(array[i] === ')')
   {
    //一直弹出直到遇到左括号
    while(stack[stack.length-1] !== '(')
    {
     let a = stack.pop();
     textArea.push(a);
    }
    //弹出左括号
    stack.pop();
   }
   else if(array[i] === '-' || array[i] === '+')
   {
    while(stack[stack.length-1] !== '(' && stack.length !== 0)
    {
     let a = stack.pop();
     textArea.push(a);
    }
    stack.push(array[i]);
   }
   else if(array[i] === 'x' || array[i] === '÷')
   {
    while(stack[stack.length-1] !== '(' && stack[stack.length-1] !== '+' && stack[stack.length-1] !== '-' && stack.length !== 0)
    {
     let a = stack.pop();
     textArea.push(a);
    }
    stack.push(array[i]);
   }
  }
  else{
   textArea.push(array[i])
  }
 }
 while(stack.length !== 0)
 {
  let a = stack.pop();
  textArea.push(a);
 }
 return textArea;
}

//计算后缀表达式
function compute(array){
 var NUMBER = [];
 for(let i = 0; i < array.length; i++)
 {
  //是运算符就计算
  if(near(array[i])){
   //加法
   if(array[i] === '+')
   {
    if(NUMBER.length < 2)
    return "错误";
    else
    {
     let a = NUMBER.pop();
     let b = NUMBER.pop();
     let c = a + b;
     NUMBER.push(c);
    }
   }
   //减法
   else if(array[i] === '-')
   {
    if(NUMBER.length < 2)
    return "错误";
    else
    {
     let a = NUMBER.pop();
     let b = NUMBER.pop();
     let c = b - a;
     NUMBER.push(c);
    }
   }
   //乘法
   else if(array[i] === 'x')
   {
    if(NUMBER.length < 2)
    return "错误";
    else
    {
     let a = NUMBER.pop();
     let b = NUMBER.pop();
     let c = a * b;
     NUMBER.push(c);
    }
   }
   //除法
   else if(array[i] === '÷')
   {
    if(NUMBER.length < 2)
    return "错误";
    else
    {
     let a = NUMBER.pop();
     let b = NUMBER.pop();
     if(a === 0)
     return "0不能作为除数";
     let c = b / a;
     NUMBER.push(c);
    }
   }
  }
  else{
   if(array[i][0] === '-')
   {
    let temp = array[i].substring(1,array[0].length);
    let num = parseFloat(temp);
    num = -num;
    NUMBER.push(num);
   }
   else{
    let num = parseFloat(array[i]);
    NUMBER.push(num);
   }
   console.log(NUMBER);
  }
 }
 if(NUMBER.length !== 1)
 return "错误";
 else
 {
  let b = String(NUMBER[0]);
  return b;
 }
}