Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
Why is q == 0 in the following script?
<script>
var start = 1234567890123456789;
var end = 1234567890123456799;
var q = end - start;
alert(q);
</script>
I would think the result should be 10. What is the correct way to subtract these two numbers?
Because numbers in JavaScript are floating-point. They have limited precision.
When JavaScript sees a very long number, it rounds it to the nearest number it can represent as a 64-bit float. In your script,
startandendget rounded to the same value.There’s no built-in way to do precise arithmetic on large integers, but you can use a BigInteger library such as this one.