Adding Numbers

How-to Discussions
1

Good day!

So, I was coding my app, and came across something interesting. If I make a function that asks to multiply two numbers:

function calculate() { var result = input1.value * input2.value / 100; tipAmt.value = “$” + result.toFixed(2);
}

This will produce a multiplied number. Now, if I use the + sign…it concatinates:

function calculate() { var result = input1.value + input2.value; tipAmt.value = “$” + result; }

So my first question is…how can I have two numbers added? And as a bonus question, once I have two numbers added, how can I have another number put in an input, that ADDS on to the previous total? Here’s the code I’m working with now:

var Observable = require(“FuseJS/Observable”); var addInput = Observable(0); var subInput = Observable(0); var calcSub = Observable(0); var totalOz = Observable(0); function addCalc() { var result = addInput.value + totalOz.value; totalOz.value = result; addInput.value = “”; } function clear() { addInput.value = “”; subInput.value = “”; totalOz.value = “”; } addCalc(); clear(); module.exports = { addCalc : addCalc, addInput : addInput, subInput : subInput, calcSub : calcSub, totalOz : totalOz, clear : clear, } + - Clear

Basically, the way this works, is you input a number at the top, it places it on the bottom (totalOz), and any additional number placed in the top field, will keep adding onto the bottom total. Here’s a working version @ codepen: http://codepen.io/0ktane/pen/NNdbOq?editors=0010

I hope this doesn’t sound like a tall order… Just need to know how to add two numbers, and keep that total to be added onto. Thanks for any assistance!

2

This is JavaScript and you should probably learn that language. + in JavaScript will add with numbers and concat strings. Try to cast it as a string either by using parseInt:

function calculate() { 
    var result = parseInt(input1.value) + parseInt(input2.value); 
    tipAmt.value = "$" + result; 
}

or implicitly like this:

function calculate() { 
    var result = 0 +input1.value + input2.value; 
    tipAmt.value = "$" + result; 
}
3

I do appreciate the information. As a side note, it came off as rude saying I should learn JS. I already do. If you looked over my post you would see that. I am still new with it though, which is why I asked for help. Though you did help, your reply came off in a negative way, any makes one not want to ask for assistance down the road.