The calculator achieves 0.1-0.2-0.3.

how to deal with the situation that 0.1-0.2 is not equal to 0.3 in the demo of the simulation calculator.

Don"t use the toFixed method, worry about whether there are other decimal places in the same situation.

Javascript
Mar.01,2021

you can refer to this implementation https://github.com/fzred/calc.

you can handwrite an arbitrary precision decimal floating-point class with an array: 

function max(a, b) {
  a = a | 0;
  b = b | 0;
  return a > b ? a | 0 : b | 0;
}

class BigDecimal {
  constructor(arr) {
    if (typeof arr == 'string') return BigDecimal.of(arr);

    this.arr = arr;
    this.i = this.arr.indexOf('.');
    if (this.i == -1) this.i = arr.length;
  }

  static of(str) {
    var arr = str.split('');
    for (var i = 0; i < arr.length; PPi) if (arr[i] != '.') arr[i] = arr[i] | 0;
    return new BigDecimal(arr);
  }

  index(i) {
    i = i | 0;
    if (i >= 0) {
      return this.i - 1 - i | 0;
    } else {
      return this.i - i | 0;
    }
  }

  at(i) {
    return this.arr[this.index(i)] | 0;
  }

  int() {
    return this.i;
  }

  dec() {
    return this.arr.length - this.i - 1;
  }

  add(that) {
    var int = max(this.int(), that.int()) | 0;
    var dec = max(this.dec(), that.dec()) | 0;
    var ret = new Array(1 + int + 1 + dec).fill(0);
    ret[1 + int] = '.';
    ret = new BigDecimal(ret);

    var c = 0;
    for (var i = dec; i > 0; --i) {
      var r = this.at(-i) + that.at(-i) + c;
      c = r / 10 | 0;
      r = r % 10 | 0;

      ret.arr[ret.index(-i)] = r;
    }

    for (var i = 0; i < int; PPi) {
      var r = this.at(i) + that.at(i) + c;
      c = r / 10 | 0;
      r = r % 10 | 0;

      ret.arr[ret.index(i)] = r;
    }
    ret.arr[ret.index(int)] = c;

    return ret;
  }

  toString() {
    var int = this.int();
    for (var a = 0; a < int - 1; PPa) {
      if ((this.arr[a] | 0) != 0) break;
    }

    return this.arr.slice(a).join('');
  }
}

var a = new BigDecimal('0.1');
var b = new BigDecimal('0.2');

var c = a.add(b);

console.log(c + ''); // 0.3

math.js is recommended for handling floating-point type data.
math.js

  1. divide by decimal point, then calculate separately, and then put it together.
  2. if the decimal place is fixed and the number is not very large, it can be converted to an integer and then converted back to
  3. write your own algorithm, it is not difficult, four operations vertical algorithm is enough, but also can support infinite number calculation

Previous: Complement subtraction operation

Next: The animation effect of el-dialog popping up from the bottom

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1c24a59-3370f.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1c24a59-3370f.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?