Question

I need some help with floating point numbers…please!

Here’s the thing, I have code like below:

<script>

    function add()
    {
        document.getElementById("answer").value = parseFloat(document.getElementById("num1").value) + parseFloat(document.getElementById("num2").value);
    }

    function subtract()
    {
        document.getElementById("answer").value = parseFloat(document.getElementById("num1").value) - parseFloat(document.getElementById("num2").value);
    }

    function multiply()
    {
        document.getElementById("answer").value = parseFloat(document.getElementById("num1").value) * parseFloat(document.getElementById("num2").value);
    }

    function divide()
    {
        document.getElementById("answer").value = parseFloat(document.getElementById("num1").value) / parseFloat(document.getElementById("num2").value);
    }

</script>

Sorry it’s a bit long! And then the html is pretty simple:

<h1>Calculator</h1>

<h3>Enter a value in each box below, then click an operation</h3>

<form id="calculatorForm">
    <input id="num1" value="0" type="text">
    <input id="num2" value="0" type="text">
    <br>
    <input value="+" onclick="add();" type="button">
    <input value="-" onclick="subtract();" type="button">
    <input value="*" onclick="multiply();" type="button">
    <input value="/" onclick="divide();" type="button">
    <br>
    <input id="answer" value="0" type="text">
</form>

You can pretty much guess what my question is gonna be: when I multiply, divide, or subtract two floating point numbers, I end up with an infinite decimal.

I need a quick solution that will round those numbers to two decimal points, and I need it to work later on, because I then need to implement Fahrenheit-to-Celsisus operations afterwards.

I don’t care how this is done, but it must be Javascript. Sorry if this has been answered before, but I really need an answer soon! Thanks!

EDIT: A BIG Thankyou to the helpful people who answered my questions. Thank you!

Answer 1

Use .toFixed():

var num = 45.34343434343;

num = num.toFixed(2); // "45.34"