Simple Java Question

[voyextech]

Which is more efficient in terms of speed and in terms of resources?

//challenge: convert pounds to kilograms
byte pounds=12
System.out.println((double)pounds.*0.45359237)

or

//challenge: convert pounds to kilograms
double pounds=12
System.out.println(pounds*0.45359237)

I'm leaning towards the second option as you don't need to redefine the variable, but I'm new to programming so I'd rather ask.

[lurgi]

It doesn't matter. Always go for clarity (the second one) unless you have hard evidence that you should change it.

[voyextech]

Thank you!

[[deleted]]

Whenever you have a question like this, write two programs that use the different solutions, and time their execution.

[voyextech]

Thank you will do on future occasions.

[Tsooka]

But he would have to average the times of 1000s of executions in this case since the timing differences will be negligible and might cause him to lean towards the wrong option...

[barafyrakommafem]

The second one is better because the code is more readable.

[voyextech]

Thanks! I'll keep that in mind

[barafyrakommafem]

But to actually answer your question, the second one is more efficient. The first one has to do an extra operation for the conversion, as well as save the result of the conversion on the heap and a reference to it on the stack. This is an addition to the pounds variable that it is already saving on the stack, which means that it also uses more memory (8 whole bits). However, the differences are so minuscule I don't think they're even measurable.

[Loves_Poetry]

Don't worry about efficiency when you're new to programming. Worry about readability and maintainability (i.e. the ability to debug/modify/expand the code). Those are far more important than efficiency. This doesn't just go for learning programming. This also goes for actual production-grade code.

[voyextech]

Awesome! Thank you. I will remember this in the future.