How to convert a double to long without casting?

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What is the best way to convert a double to a long without casting?

For example:

double d = 394.000;
long l = (new Double(d)).longValue();
System.out.println("double=" + d + ", long=" + l);
type-conversion java
8 Answers

Assuming you're happy with truncating towards zero, just cast:

double d = 1234.56;
long x = (long) d; // x = 1234

This will be faster than going via the wrapper classes - and more importantly, it's more readable. Now, if you need rounding other than "always towards zero" you'll need slightly more complicated code.

user_226560

... And here is the rounding way which doesn't truncate. Hurried to look it up in the Java API Manual:

double d = 1234.56;
long x = Math.round(d); //1235
litb_345090

(new Double(d)).longValue() internally just does a cast, so there's no reason to create a Double object.

user_135310

Simply by the following:

double d = 394.000;
long l = d * 1L;
user_40782680

Simply put, casting is more efficient than creating a Double object.

user_274740
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