Java

[Divinity]

I'm taking a course and it's having me explain each line of code in a java program. I'm meant to comment and describe what the line of code does or why it is necessary. Problem is, I just don't get it..

I've researched stuff online but it doesn't tell me what the purpose is for each data type and so forth.

If any of you know a good website that explains it (since I can't seem to find one) or mind explaining it to me, I would greatly appreciate it.

Thanks in advance!

[g++]

Be glad to help but its kind of like saying "I dont get french" its not really a good launch point to learn useful information. Is there something particular you dont get about java?

[g++]

Anyway if you already have a decent grasp of java I know it sounds pretty obvious but you can just go to sun microsystem man pages for java. It has everything you ever wanted to know about prepackaged functions and objects.

http://java.sun.com/docs/books/tutorial/ tutorials
http://java.sun.com/javase/7/docs/api/ the java api

if you have a specific problem can probarbly help unless it involves networking or something...and then your on your own because I confuse myself with that shit.

[diethx]

Java is shit. It turned me into angry German kid a few years ago.

[g++]

I wrote an assemly language program a couple months back that actually laughed at me because the out of bound memory it was accessing was full of smiley face characters for some reason so when I overflowed the buffer it just scrolled smiley faces infinitely, I actually screen shotted it to prove my computer is evil.

[BigWorm]

Java is shit. It turned me into angry German kid a few years ago.

Java's not bad. The syntax is good for OO, the libraries have the vast majority of stuff that you need, and the portability is awesome. theReallyLongCamelCaseVariableNames can get kind of annoying, but at least its not Visual Basic.

[diethx]

Java's not bad. The syntax is good for OO, the libraries have the vast majority of stuff that you need, and the portability is awesome. theReallyLongCamelCaseVariableNames can get kind of annoying, but at least its not Visual Basic.

I probably would've had a much easier time if my professor for my first Java class wasn't completely inept and actually gave me a good foundation, which she unfortunately didn't. Things got slightly better once someone told me about Eclipse and I started using that instead of JGrasp, which is all I was supposed to use. However, I still say, Java is shit and i'd rather shave my head than program in it again.

[g++]

I feel exactly the opposite. Java feels intuitive to me. Staring at c code for days on end trying to find where a block of memory you allocated 6 classes ago is what gives me nightmares. Although java is slow obviously.

[Divinity]

Well.. I think I pretty much have it? I'm not sure if I'm right or not. I feel like I've been thrown into this without any prequisite for knowledge.




/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/

package lab1; /* This identifies the program as the first lab */
import java.util.Scanner; /**
* This line makes a program easier to read. The Scanner parses strings and
* variables using expressions.
*/


/**
* @author Sarah Bermudez
* October 9, 2009
* The purpose of the program is to calculate a formula by assigning a
* value to each variable.
*/
public class Main {
/**
* public class Main { let's the computer know where to start the program.
*/
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
int i, j; //
/**
* i and j are integers. int declares the variable type for i and j.
* int is a data type that is used to store a whole number as a value.
* int is needed to store the information.
*/
char c; //
double x; //
/**
* char is short term for character and c is the value. double is another data
* type and is a double precision which means it won't truncate intergers.
*
*/
i = 4; //
j = i + 7; //
c = 'A'; //

x = 9.087; //

x = x * 12.3;
/**
* Above are the assigned values for each variable. This tells the program
* what to input for each variable in the expression below. Since a double
* precision was used, 9.087 won't be truncated. Without 'double' being used
* x would have been used as 9 instead. These are needed to solve the
* calculation.
*/
System.out.println("i is " + i + ", j is " + j + ", c is " + c + ", x is " + x); //" +
/**
* System.out.println echoes the information and displays it into the designated
* output that's defined by the program. In this case, the information is
* displayed in the output window.
*/

/**
* Output: i is 4, j is 11, c is A, x is 111.7701
*/



}


So, each line of code I'm supposed to tell it's purpose or function. Explain it and put it in C style comments.

Thing is.. I can define what it is but I don't know it's purpose. :/

[Celephais]

Umm... okay well package is for defining the package the code lives in, so the class you're creating is lab1.Main. The imports is to allow you to reference classes in that package without using the full name... so if you had "imports System;", instead of saying "System.out.println" you could just have "out.println".

You should also mention that char is a data type, and c is the variable, not the value.

maybe you should say 'if int were used instead of double' instead of 'without double being used'

Otherwise that's probably fine.

[phantasm]

package lab1; /* This identifies what package this file belongs too */
import java.util.Scanner; /** Import the scanner class from the java standard library */


/**
* @author Sarah Bermudez
* October 9, 2009
* The purpose of the program is to calculate a formula by assigning a
* value to each variable.
*/
public class Main { /* definition of main class, with public visibility */
/**
* @param args the command line arguments //javadoc
*/
public static void main(String[] args) { //execution entry
int i, j; /* declare 2 integer variables named i and j */

char c; // declare character variable named c
double x; // declare double variable named x

/**
* assign values to the variables
*/
i = 4;
j = i + 7;
c = 'A';
x = 9.087;
x = x * 12.3;

System.out.println("i is " + i + ", j is " + j + ", c is " + c + ", x is " + x); //write to system output

} // end of execution

}//end of Main class definition

Here's how I would do it.

[Divinity]

That's cool phantasm but what does all of that mean? Lol.

Thanks for the explanation, Cel.

[phantasm]

I think you should be learning this from your well paid instructor, not from me.

[Divinity]

I think I should be too but sadly she's in China and told us to do a hunt and find. I'm probably going ahead of what I needed to do but I like to learn what I'm trying to find.

Even though this thread is about asking for someone to help me out. Why even bother with all of that if you didn't want to explain it in the first place? >.>;;

[Celephais]

Is there anything in that program that still doesn't make sense to you or you want clarification on? I'm a .NET guy myself (mostly C#), but it's pretty close to java, and I do develop java on occasion for one client (as well as having a java developer housemate).

Specifically what part don't you understand the meaning of?

[Divinity]

I guess I'm having trouble understanding intergers, variables and values. I thought variables and values were interchangeable so I don't know why you would have to assign a value to a variable if you can just change the variable. I don't even know if what I just said made sense. Lol. Man, I feel dumb and usually I pick up on this stuff pretty fast.

Is this similar to understanding algebra? It would seem so but I don't want to put myself in that mindset and fuck myself over by using the same definitions.

[Celephais]

When you say:
int i;
You're asking the computer to reserve enough space for an integer in memory, and to call that space "i". That reserved space does not yet have a value (although it'll likely default to 0). So that variable, i, is currently unassigned.

When you assign a value to i, it stores that value in the space in memory reserved for i. So by saying i = 4, you place "4" in that space. The variable is still i, but the value is now 4. That value can be changed, but the variable is still named i.

So one way to think of it is that the variable is the bucket, and the value is the contents.

When you later say something like:
j = i + 7
You're actually saying j equals the value of i plus seven.

That clarify it a bit?

[Divinity]

Cel, thank you SO much. I get it now. You're awesome!

[phantasm]

Just wait until you have to parse a complex unverified XML file with DOM.
Why are you learning to code?
It takes a person that is really fucked in the head to enjoy this shit.

EDIT: Sorry, I'm apparently terrible at explaining things, I was 100% sure my comments on your code would explain it completely.