Java Variables

[grimFandingo]

Hello everyone;

 

So I have decided to learn Java after many years out of the game (was a C programmer)

 

I already decided I hate the variables system, so I need some help... (Bear in mind this is not the actual code I am using this is just to make it easier)

 

Say I have one variable in a method in a class that is not the main class

public void method1(){int a = 1System.out.println(a + 1);}

then I want to use it inside another method in the same class

public void method2(int a){System.out.println("a + 2")

So far this is fine, but here is my issue.

 

When I want to call method2 in my main class I get the error "a cannot be resolved to a variable"

 

Here is what I am doing:

 

I am turning the method into an object and then calling it like I do with methods without parameters:

testClass method2obj = new testClass();method2obj.method2(a);

I am not sure what to do here, any ideas?

 

Thanks guys

 

 

[zahlio]

public void method2(int a){   System.out.println(a + 2);}

then to call:

method2(5);

outcome:

7

[Darkfeign]

testClass method2obj = new testClass();method2obj.method2(a);

 

What exactly are you trying to do here? It's stating a cannot be resolved to a variable, because in this code the variable a has not been set, and so it does not exist. If you're attempting to use the value of a inside the class, then you need to reference it, such as:

 

method2obj.method2(method2obj.a);

Though I haven't touched java in about 6 months now so I might incorrect in the referencing method used, but you need to ensure that the variable is public and accessible outside of the class. That, or you need to simply define a before calling method2() in your main function (or wherever you're calling it) as without an object-specific reference, Java does not attempt to retrieve the instance variable, and instead looks for a locally scoped variable, a.

[grimFandingo]

Thanks guys, my problem is solved;

 

just quickly though,

 

is there a way to run a method only the first time an application is ran then never do it again. It will save the required details and remember them for next time. Is this possible without incorporating a database?

[grimFandingo]

Doesn't matter, I used an array and found the answer 

 

[zahlio]

Doesn't matter, I used an array and found the answer 

do you care explaining what fixed the issue in the first place :)

[rashdanml]

I would assume you can store the array to a file, and read the file every time the program is launched. If file exists, don't run method. If file doesn't exist, run method. Can't do it purely with arrays/variables, as everything is reset when you close a program. Files are the simplest choice for small amounts of data, databases for large amounts of data.