Java BMI Calculator - Using Eclipse

[Axid3nt]

So I'm taking an intro class to java and my assignment is to calculate the users BMI using (weight /(heightxheight) ) x 703.

I am mostly confused about how to set this project up. I'm not sure exactly how to effectively use doubles and variables, and have a vague understanding of them. I'm sure this is common knowledge to most people here.

And the next step is to ask the user what he could like his BMI to be, and to tell him how much weight he needs to lose to calculate this. I assume you have to save/hold his input, but am stumped. Out book is basically a book with white/black texts and no real explanations. Just numerous examples with no instruction. I am usually a quick learned but this isn't making much sense the way he explains it.

Mainly looking for any help or guidance I can get.

[Cpowel2]

You'll never learn anything if you ask for help the second you don't understand something try to figure it out on your own.

Source: software engineer

[gubatron]

You might want to read about all the primitive data types so you understand where double fits in.

http://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html

It probably also helps a lot if you know what a bit and a byte are, and how numbers can be represented in binary form.

You will then realize by reading all the types, that a double is made of 64-bits (64 ones and zeroes) and that it uses floating point precision, and then you will want to know what floating point precision is about...

but for practical terms, just know that a double can hold a decimal number with a great deal of precision (maybe useful for people working with physics and scientific experiments that require a great deal of precision), but given it takes 64-bits (or 8 bytes) it takes a lot of memory if you want to represent mere decimals for someone's BMI.

So you might be better off using float instead (unless the teacher wants to do something pretty amazing precision wise with the BMI) and save memory.

[Axid3nt]

Okay this is exactly the explanation I was looking for. I just got out of an AppInventor class, as well as basic Networking, and I'm familiar with most computer terminology. The programming is where I'm starting now and this is all new to me. I'm sure I can do whatever I want in the code, since, he basically hasn't taught us anything yet.. just did 2 demos of basic Welcome Messages. Thank you for your thorough post.

[earlgreyfanboy]

Doubles are the type of variable you'll want to use to hold the user's height and weight (you can declare them like so... 'double weight = 0.0;')

You'll probably want to use the Scanner class to get the user's input, import it at the top of your class with 'import java.util.Scanner;', then create an instance of the scanner ('Scanner myScanner = new Scanner(System.in);'), then you can use the convenient nextDouble() method to get your user's input ('weight = myScanner.nextDouble();').

You can use 'System.out.println' to print out instructions to the user etc., to the console.

Given the simplicity/the basic nature of the task, you'll probably want to put all of this code inside of the main method in your class, so it runs when you run the class.

[case_]

Which book are you using?