Thread: complex input parsing

Hello everyone!

I have a problem where i don't know how to start.
As a java beginner i'm lacking knowledge how to best achieve what i intend to to.

What i intend to do:
writing some calculator-like thing but not like the simple ones where you press your buttons for 0-9 plus buttons for certain operations like + ,- and so on.
What i want is a textfield where you can input things like 2 + 2.32 + (double) 1 - 2.34434f and get the result plus the data type this would have in java.
So what i want to create is like a small training programm where people (including myself ) can input java expressions and test their understanding of casting and automatic type conversion. In this way i can learn something about how to work with input and about javas mechanics at the same time.

Is there any efficient and understandable way a beginner could do this?
Thanks in advance for any advice and help!

There is no way to pour into your head while you sleep the knowledge and skills needed to accomplish what you've described. It's a reasonable project (though I find the idea of specifying the data type annoying - the calculator should just deal with whatever is entered) but somewhat advanced for someone without much Java experience and little/no GUI experience. But you have to start somewhere.

I recommend you start with the Java Tutorials, ignoring the parts about using the Netbeans GUI Builder.

O_o...i asked in a proper manner..i don't know why i deserve such harsh words.

and what is annoying about the idea of specifying the data type? i personally would find that usefull...

There was no intent to be harsh, and I apologize if I overstated my point, which was:

There are no short cuts or guaranteed efficient ways to learning a programming language and becoming proficient and skillful at it. Further, jumping straight to GUI programming without a solid foundation of understanding and experience in programming basics is usually a mistake. If you're already aware of programming basics in another strongly-typed, object-oriented language, including data types, variables, branching, looping, methods/function/subroutines, objects and classes, and arrays, then you should be able to pick up GUI programming in Java using the link I provided above. If you're completely new to programming, then you should spend a few weeks or months studying those topics I listed, writing several examples and exercise programs on each topic. Here's a good, free online book that I recommend to get started. There are links to others I can provide, if you don't find this one understandable. The Java Tutorials is also a good place to start.

As for a calculator where the user specifies the data type, we can each have our own thoughts on that, and I am not trying to change yours. However, I would suggest that the calculator interface include the ability to specify the data type in some way other than typing it. A graphical interface, should require as little use of the keyboard as possible.

Good luck, and please come back when you need help!

Originally Posted by Wolfone

I have a problem where i don't know how to start.
...What i want is a textfield where you can input things

Start there

ok i c...maybe i overreacted. and yes i have way more theoretical knowledge than practical. as a mathematician i did a lot of programming in matlab and algorithms, loops, branches and so an are not the problem. maybe i want too much for now...

i am aware of the fact that i may be doing things at the moment which aren't necessarily done that way. i don't know. i do it this way to learn something about this specific language and how it works. so first i did was playing around with classes and inheritance, learning how constructors work, how to overload, and so on...doing a little bit of GUI to see if my expectations are met.
well...i will start as jps said with a textfield that shouldn't be the bigger problem. maybe something that manipulates a string and gives back the manipulated string.
started reading the GUI tutorial ^^

thanks you 2