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JavaScript Object-Oriented JavaScript (2015) Introduction to Methods Finishing the Calculator

Posted by MUZ140759 Kelvin Mutukura
MUZ140759 Kelvin Mutukura
6,549 Points

Implement the subtract method

I'm stuck here

calculator.js 
var calculator = {
  sum: 0,
  add: function(value) {
    this.sum += value;
  },
  subtract: function(value) {

  },
  multiply: function(value) {

  },
  divide: function(value) {

  },
  clear: function() {
    this.sum = 0;
  }, 
  equals: function() {
    return this.sum;
  }
}
Christian Andersson
Christian Andersson
8,712 Points

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3 Answers

Colton Ehrman
Colton Ehrman
Courses Plus Student 5,859 Points

Not really sure how your calculator should work, but I would think that subtract would be the opposite of add so 

this.sum -= value;
MUZ140759 Kelvin Mutukura
MUZ140759 Kelvin Mutukura
6,549 Points

Thanks Colton

Colton Ehrman
Colton Ehrman
Courses Plus Student 5,859 Points

No problem :)

Colton Ehrman
PLUS
Colton Ehrman
Courses Plus Student 5,859 Points
Colton Ehrman
Colton Ehrman
Courses Plus Student 5,859 Points

Check out this way of doing your calculator 

var calculator = function(val){
  this.sum = val;
  this.add = function(value) {
    this.sum += value;
    return this;
  };
  this.subtract = function(value) {

  };
  this.multiply = function(value) {

  };
  this.divide = function(value) {

  };
  this.clear = function() {
    this.sum = 0;
  };
  this.equals = function() {
    return this.sum;
  };
  return this;
};

console.log(calculator(6).add(6).equals());

Now just implement the other methods as I did with this.add, and now you can chain methods and then when your ready to see the end result just call equals.

jeannieduen
seal-mask
.a{fill-rule:evenodd;}techdegree
jeannieduen
Front End Web Development Techdegree Student 8,709 Points
jeannieduen
.a{fill-rule:evenodd;}techdegree
jeannieduen
Front End Web Development Techdegree Student 8,709 Points

What is the answer to this challenge!?!?!? I am forever stuck on this.

Shaun Wong
Shaun Wong
14,489 Points
Shaun Wong
Shaun Wong
14,489 Points

Did you see the solution above? Just in case you are still stuck forever... i've given you the answer below.

Check out this for shorthand multiply and division https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Assignment_Operators

var calculator = {
  sum: 0,
  add: function(value) {
    this.sum += value;
  },
  subtract: function(value) {
    this.sum -= value; 
  },
  multiply: function(value) {

  },
  divide: function(value) {

  },
  clear: function() {
    this.sum = 0;
  }, 
  equals: function() {
    return this.sum;
  }
}