toya kin

Hi guys,

I am a windows user even though i'm not proud of it. One day i used the "Disk Clean-up Wizard"
and then after that i found that when i run my compiled class files it always give me

Exception in Thread "main" java.lang.NoClassDefFoundError: <ClassName>

and i asked my friend and he said that it's probably the windows env variable CLASSPATH or Path is altered, so i changed them both to (added) the JDK bin folder, and i rebooted but i still get the same error message

so if anyone have experienced a same problem or are able to help me i'd really appreciate it

hi guys, thanks for your attention btw
so i've come to something weird that made me think that no changes to a JPanel can be done inside the actionPerformed method

so here is how it started
Say that you want to change the whole content of a panel (i think...)
the easiest thing to do is just probably create another panel then you do whatever you do inside that new panel, when you want to change it, just remove that newly created panel then create and add another one
so i made a button that when clicked remove a panel, then add another one to the main container (the one i got from getContentPane()), but it didn't work, so then i tried adding pane.validate() and pane.repaint() (pane is the main container) and they didn't work either
and then i checked both my textbooks and found that they don't have in depth discussion on these things

so i would really appreciate if someone points me the direction to a tutorial on this or explain it to me directly
thx

well, you made it like that
else { System.out.println("Error"); System.out.println("Please enter a number between 1 to 4 and hit enter: : "); }

and there is a logic error, if you want the user to keep inputting until he has inputted it correctly then
while (inputNumber <=4) { inputNumber = stdin.nextDouble(); }
will make user keep inputting a double until they inputted a value that is above 4.0 (which is what you DONT want)

should be something like this
System.out.print("Enter a number between 1 and 4 : "); inputNumber = stdin.nextDoube(); while (inputNumber < 1 || inputNumber > 4) { System.out.print("ERROR: please enter number between 1 and 4 :"); inputNumber = stdin.nextDouble(); }

and i wonder why you don't use switch, and why you use double for the input number, because this can cause user to be able to input a double value.