Thread: calculation in GUI interface

Hello there,

I'm trying to create a GUI interface in Netbeans that calculates a phone bill.

I created a GUI interface that input:
- Account Name.
- Account Number.
- Number of Minutes the phone was used. (with a textarea so the user input the minutes)
- 2 JRadioButtoms so the user can chose the regular or premium service.
- Amount Due (+10% taxes) (also with a textarea)
- Clear/Enter/Result/Done Buttoms

And I need to output:
- Account Name.
- Account Number.
- Number of Minutes.
- Taxes
- Total Amount Due.

I have a couple of math formulas I have to add them to output the above however I'm new to java so I don't know which code to use.

The math formulas are:
-Regular charges = 20 + ( No. Minutes - 50 ) * 0.20
-Premium charges = 50 + ( No. Minutes - 75 ) * 0.50
-Taxes = ( Regular charges + Premium charges ) * 0.10
-Amount Due = Regular charges + Premium charges + Taxes

I tried different methods but they don't work. i thing there was something wrong with the code. also, i named each variable a name and i wrote -- System.out.print((a+(min. + c) * b)); -- something like that.
but i don't know which code to use i'm kinda slow with java loooool

private void ENTERActionPerformed(java.awt.event.ActionEvent evt) {
//- Regular charges = 20+ ( R min – 50)*0.20
//- Premium charges = 50+ ( P min – 75) * 0.50
//- Sales tax=(R charges + P charges)*0.10
//- Amount due= Regular charges + Premium charges + Sales tax
double a = 20;
double b = 50;
double c = 0.20;
double d = 50;
double e = 75;
double f = 0.50;
double rmin = Double.parseDouble(NMTEXT.getText());
double pmin = Double.parseDouble(NMTEXT.getText());
System.out.print((a+(rmin-50)*c));

}

I think you should first of all understand the problem you are trying to solve before solving it.You said you wanted to develope a programm to calculate phone bill ,from your code i cant connect the problem with the code you have there.Try to be more explicit.