Java

The main purposes of learning java

13-Jul-16 23:15

Given your question, what else could you search for?

Ratul Thakur24-Jun-16 4:04

24-Jun-16 4:04

hi,
i'm an experienced C++ , C# and Python programmer. Now i'm thinking of learning java (i know the basics though).
But i'm wondering what will be the use of that... i know Java is pretty popular, but it cannot run without JRE (i.e. it does not support standalone executables) and the source code is also visible (even you can extract the .jar files and view the source code).I'm also an opengl programmer (with C++), and i've seen some opengl game tutorials with java, so the question arises that where those games will be played.. ive never seen a game with .jar executable.Im also known to the popular SWING toolkit, but where are those SWING apps used, i've never seen one. So i want to know the main purpose of learning java. And i've also got my environment ready with JDK and eclipse. Thumbs Up | :thumbsup:

Richard MacCutchan24-Jun-16 4:27

24-Jun-16 4:27

Ratul Thakur wrote:
So i want to know the main purpose of learning java.

The same purpose as learning any language: to develop applications. Whether for your own amusement, or as a requirement of your employment, is up to you to choose.

Ratul Thakur24-Jun-16 5:04

24-Jun-16 5:04

no no... i dont need employement Laugh | :laugh:

im just 15,
i mean ... .... well... i want to know that if i create a GUI app on swing, where will that be used?? ..ive never seen a commercial app developed in swing, neither a 3D opengl game in the .jar file format. Or is there a way to make platform specific binary executables??
Thanks for your help!

Richard MacCutchan24-Jun-16 5:09

24-Jun-16 5:09

Ratul Thakur wrote:
if i create a GUI app on swing, where will that be used?

Anywhere that you can get people to use it.

Ratul Thakur wrote:
is there a way to make platform specific binary executables?

No need, java is write once, run anywhere.

Ratul Thakur24-Jun-16 5:16

24-Jun-16 5:16

thanks mate, i searched google... and i think my main purpose of learning java is going to be android developement
getting started now!! ive got a pdf from tutorialspoint.com . Thumbs Up | :thumbsup:

Richard MacCutchan24-Jun-16 6:22

24-Jun-16 6:22

Take a look at http://www.codeproject.com/KB/android/#Android+Tutorial+Contest[^] for some excellent Android tutorials,

DannyFreeman28-Jun-16 6:25

DannyFreeman

28-Jun-16 6:25

Most platforms have the JVM installed, so it's not necessary to make an executable. You can make a standalone executable if you want, but you will loose Java's portability.

Releated stack overflow question.

Instead of Swing you should the newer GUI library, JavaFX. As far as games go, LWJGL is used for making games in Java. Minecraft was originally written in Java.

Ratul Thakur29-Jun-16 3:43

29-Jun-16 3:43

thanks
i've completed half of the book on java programming.... and i find this language great. And then i'm planning to learn JavaFX and then probably OpenGL with java for android developement.

Kimberly Weldon5-Jul-16 22:59

Kimberly Weldon

5-Jul-16 22:59

These are the reasons that I personally came up with:

Java has a very rich API, and an incredible supporting open source ecosystem. There are tools upon tools for just about everything you would like to do.

Java is an Object Oriented language. It internally embraces best practices of object oriented design.

The IDEs available for Java will blow your mind.

Java is running just about everywhere you can imagine. It’s usually where most large applications end up due to its scalability, stability, and maintainability.

All Android Apps are written in Java.

Java is a verbose language, which at first can seem daunting. However, after learning the basics you’ll find that you can easily grab onto more advanced concepts because the code is very explicit.

Hope it will help you!

Richard MacCutchan6-Jul-16 0:56

6-Jul-16 0:56

Kimberly Weldon wrote:
All Android Apps are written in Java.

Not true, many are now written in C, C++, C# etc.

Ratul Thakur8-Jul-16 1:05

8-Jul-16 1:05

who will prefer C++ over java if both languages are gonna give the same result?! Big Grin | :-D

Richard MacCutchan8-Jul-16 3:05

8-Jul-16 3:05

Probably all those people who have not learned Java and do not want to start now.

Ratul Thakur8-Jul-16 1:03

8-Jul-16 1:03

i've completed 60% of the book by now.... its syntax it quite similar to C#
and netbeans is blowing my mind Laugh | :laugh:

..i recently found out that it was written in java...
but the newer versions of visual studio are way better than it.

simple question nested for loop to solve array problem

Pratik Temkar3-Aug-16 3:32

Pratik Temkar

3-Aug-16 3:32

You did great man.....

Member 1259386520-Jun-16 4:29

Member 12593865

20-Jun-16 4:29

Hi guys I gave up on this code ! trying figure out how if condition became true ! since

Java

never will be greater than

Java

	public static void main(String[] args){
	    int a[]={4,2,7};
	     
	    
	    for(int i=0; i< a.length ;i++) { // here i =0 then a[0]=4
	    
	        for(int j=i; j< a.length ;j++) { // here also j=i since i=0 then j=0 too,  a[0]= 4
	        
	        	if (a[i]>a[j]){ // when a[i] will be > than a[j]
	        		
	        	System.out.print("condition is match "); 
	        		
	        	}

	        }
	    }
}

i start with 0 
     j start with 0 
     j became 1 
     j became 2

i became 1 
   
     j start with 1 
     j became 2 
     

i became 2 
   
     j start with 2 
     

I got confuse ,

modified 20-Jun-16 13:57pm.

Re: simple question nested for loop to solve array problem

Richard Deeming20-Jun-16 5:46

Richard Deeming

20-Jun-16 5:46

You're not comparing i to j; you're comparing a[i] to a[j].

Look at what happens when i = 0 and j = 1:

a[i] == 4
a[j] == 2

a[i] > a[j] 
=== 4 > 2 
=== true

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Re: simple question nested for loop to solve array problem

Member 1259386520-Jun-16 8:04

Member 12593865

20-Jun-16 8:04

Thank you Richard for your replay in fact, this is my question how on the second loop j start with 1 ? should start with 0 since j always j=i ; and i start with 0 , then j will be 0 so a[i] will be 4 and a[j] will be 4 ?

Java

for(int i=0; i< a.length ;i++) { // here i =0 then a[0]=4

           for(int j=i; j< a.length ;j++) { // here also j=i since i=0 then j=0 too,  a[0]= 4

modified 20-Jun-16 14:16pm.

Re: simple question nested for loop to solve array problem

Richard Deeming20-Jun-16 9:09

Richard Deeming

20-Jun-16 9:09

j doesn't start with 1; it starts with i, and then increments for each pass of the inner loop.

i = 0
    j = 0    a[i] = 4; a[j] = 4
    j = 1    a[i] = 4; a[j] = 2    // <-- Your condition is met here
    j = 2    a[i] = 4; a[j] = 7

i = 1
    j = 1    a[i] = 2; a[j] = 2
    j = 2    a[i] = 2; a[j] = 7

i = 2
    j = 2    a[i] = 7; a[j] = 7

You really need to learn to use a debugger. Rather than trying to guess what your code is doing, step through it line by line and examine the values of the variables.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Re: simple question nested for loop to solve array problem

Member 125938652-Jul-16 17:52

Member 12593865

2-Jul-16 17:52

I came over this post again , it surprise for me to not see my last post ,

any way, Dear Richard thank you so much for clearing the process steps of loop , I really appropriate your time. and i'm sorry to replay back late i just shack to not see my thank you post I may closed the browser before public the post

Rose | [Rose]

3 x 3 plane,clockwise or counterclockwise rotate the four tiles

zarkerBlack20-Jun-16 0:43

zarkerBlack

20-Jun-16 0:43

There're 9 numbers in a 3 x 3 plane. We could only clockwise or counterclockwise rotate the four tiles around one of the four points, I II III and IV. R1, R2, R3, R4 and r1, r2, r3, r4 are corresponding to the 8 kinds of rotation, where we mark clockwise rotations as r and counterclockwise rotations as R. For example, starting from configuration (S), by the rotation sequence r1R4r2R3 we reach the configuration (E). Now, starting from configuration (S), find the shortest way to reach configuration (T).

If I want to program to solve the problem，do you have any good idea?
[Cilck here for detail picture]

Re: 3 x 3 plane,clockwise or counterclockwise rotate the four tiles

Richard Deeming20-Jun-16 1:40

Richard Deeming

20-Jun-16 1:40

Your homework is set to test what you know, not how good you are at getting strangers to do your work for you.

Try it yourself. It should be based on concepts that you have recently covered in your course, so you'll probably find it's actually not as difficult as you think.

If you don't know where to start, then talk to your teacher.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Re: 3 x 3 plane,clockwise or counterclockwise rotate the four tiles

zarkerBlack20-Jun-16 3:09

zarkerBlack

20-Jun-16 3:09

that't not homework,my friend ask me the question, I think it's funny, so I want to solve it with an Android app,traversal need too much steps,so I need an idea about math models

Re: 3 x 3 plane,clockwise or counterclockwise rotate the four tiles

Richard MacCutchan20-Jun-16 4:00