loops, what the heck?!?

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machoextreme - 06 Dec 2005 20:31 GMT

Once again, I'm having trouble with some code (this group has already
gotten me out of a few jams). I'm writing a seemingly simple
temperature conversion program, and it works great. I have gotten it to
compile and everything. The problem; I can't get it to loop (yes this
is my first attempt to work a loop into a program). I was trying to
allow the user to return to the initiation code at the beggining of the
program and repeat the options using to Do-While method, but I must be
getting the placement of the while statement, or something equally
stupid, but I just can't figure this help. Could someone look at my
code and instruct me on how exactly to work a loop into a program?!?

import java.util.*;

public class mlounsburyproject2
{
    public static void main(String[] args)
{
    do{
    float degreesC;
    float degreesF;
    String nextent= "";
    Scanner keyboard= new Scanner(System.in);
    System.out.println("Welcome to the temperature convertor program");
    System.out.println("Please choose the temperature format you wish to
convert from, C or c for celsius, F or f for Fahrenheit");
    String format = keyboard.next(); // returns a single word excluding
blanks
    char letter = format.charAt(0); // get the first character which is
supposed to be the one the program is waiting for
    if (format.equalsIgnoreCase ("c"))
    {
        System.out.println("Please enter the temperature in Celcius that is
to be converted" );
        degreesC= keyboard.nextFloat();
        degreesF= ((9 * (degreesC)/5) + 32);
        System.out.println("The converted temperature is " +degreesF +"
Fahrenheit");
        System.out.print("Press q or Q to quit the program, or any other key
to start over ");
        nextent= keyboard.next();
        if (nextent.equalsIgnoreCase("q"))
            System.out.println("Goodbye");
            System.exit(0);
        }

    else if (format.equalsIgnoreCase("f"))
    {
        System.out.println("Please enter the temperature in Fahrenheit that
is to be converted" );
        degreesF= keyboard.nextFloat();
        degreesC= (5 *(degreesF - 32)/9);
        System.out.println("The converted temperature is " +degreesC + "
Celsius");
        System.out.print("Press q or Q to quit the program, or any other key
to start over ");
        nextent= keyboard.next();
        if (nextent.equalsIgnoreCase("q"))
            System.out.println("Goodbye");
            System.exit(0);
    }

    else
    {
        System.out.println("That is not a valid selection, please try again
");

    }

    }while (true);


}
}

Reply to this Message

Monique Y. Mudama - 06 Dec 2005 20:42 GMT

> Once again, I'm having trouble with some code (this group has
> already gotten me out of a few jams).

Please don't multipost. Posting to the help group was almost
certainly the right thing to do.

Signature

monique

Ask smart questions, get good answers:
http://www.catb.org/~esr/faqs/smart-questions.html

Reply to this Message

Patrick May - 07 Dec 2005 08:26 GMT

> Once again, I'm having trouble with some code (this group has
> already gotten me out of a few jams). I'm writing a seemingly simple
[quoted text clipped - 7 lines]
> help. Could someone look at my code and instruct me on how exactly
> to work a loop into a program?!?

[ . . . ]

>         if (nextent.equalsIgnoreCase("q"))
>             System.out.println("Goodbye");
>             System.exit(0);

Your immediate problem is these three lines. You are exiting
your loop regardless of the response. What you want is:

if (nextent.equalsIgnoreCase("q"))
{
System.out.println("Goodbye");
System.exit(0);
}

The _cause_ of your problem is poor code formatting. You need to pick
a common formatting style and use an editor that automatically indents
your code for you. Your problem lines would then look like this:

if (nextent.equalsIgnoreCase("q"))
System.out.println("Goodbye");
System.exit(0);

This make the problem easier to see.

There is another thread in this newsgroup regarding the best text
editor for Java. I strongly recommend Emacs with JDEE. Others will
have different, equally strong recommendations. They're wrong. ;-)

Regards,

Patrick

------------------------------------------------------------------------
S P Engineering, Inc. | The experts in large scale distributed OO
| systems design and implementation.
pjm@spe.com | (C++, Java, Common Lisp, Jini, CORBA, UML)

Reply to this Message

Thomas Weidenfeller - 07 Dec 2005 08:33 GMT

> Once again, I'm having trouble with some code (this group has already
> gotten me out of a few jams).

What about

a) Posting to comp.lang.java.help only? F'up set.

b) What about getting a good textbook first? To macho for that' eh?

> public class mlounsburyproject2

c) What about following Java's naming conventions?

/Thomas

Signature

The comp.lang.java.gui FAQ:
ftp://ftp.cs.uu.nl/pub/NEWS.ANSWERS/computer-lang/java/gui/faq
http://www.uni-giessen.de/faq/archiv/computer-lang.java.gui.faq/

Reply to this Message

Stefan Schulz - 07 Dec 2005 14:36 GMT

> Once again, I'm having trouble with some code (this group has already
> gotten me out of a few jams). I'm writing a seemingly simple
[quoted text clipped - 6 lines]
> stupid, but I just can't figure this help. Could someone look at my
> code and instruct me on how exactly to work a loop into a program?!?

[SNIP]

I am usually more helpful in cljh, but here let's see how macho you really
are. Hand this in to your professor / teacher... and let me know what
(s)he thinks, will you?

import java.util.Scanner;

class YourHomework {

static final Scanner $_ = new Scanner(System.in);

private static char [] data = {
0x15, 0x27, 0x2e, 0x21, 0x2d, 0x2f, 0x27, 0x62, 0x36, 0x2d,
0x62, 0x36, 0x2a, 0x27, 0x62, 0x36, 0x27, 0x2f, 0x32, 0x27,
0x30, 0x23, 0x36, 0x37, 0x30, 0x27, 0x62, 0x21, 0x2d, 0x2c,
0x34, 0x27, 0x30, 0x36, 0x2d, 0x30, 0x62, 0x62, 0x32, 0x30,
0x2d, 0x25, 0x30, 0x23, 0x2f, 0x6c, 0x48, 0x12, 0x2e, 0x27,
0x23, 0x31, 0x27, 0x62, 0x21, 0x2a, 0x2d, 0x2d, 0x31, 0x27,
0x62, 0x36, 0x2a, 0x27, 0x62, 0x36, 0x27, 0x2f, 0x32, 0x27,
0x30, 0x23, 0x36, 0x37, 0x30, 0x27, 0x62, 0x24, 0x2d, 0x30,
0x2f, 0x23, 0x36, 0x62, 0x3b, 0x2d, 0x37, 0x62, 0x35, 0x2b,
0x31, 0x2a, 0x62, 0x36, 0x2d, 0x21, 0x2d, 0x2c, 0x34, 0x27,
0x30, 0x36, 0x62, 0x24, 0x30, 0x2d, 0x2f, 0x6e, 0x62, 0x01,
0x62, 0x2d, 0x30, 0x62, 0x21, 0x62, 0x24, 0x2d, 0x30, 0x62,
0x21, 0x27, 0x2e, 0x31, 0x2b, 0x37, 0x31, 0x6e, 0x62, 0x04,
0x62, 0x2d, 0x30, 0x62, 0x24, 0x62, 0x24, 0x2d, 0x30, 0x62,
0x04, 0x23, 0x2a, 0x30, 0x27, 0x2c, 0x2a, 0x27, 0x2b, 0x36,
0x6c, 0x62, 0x48, 0x05, 0x2d, 0x2d, 0x26, 0x20, 0x3b, 0x27,
0x63, 0x48, 0x12, 0x2e, 0x27, 0x23, 0x31, 0x27, 0x62, 0x27,
0x2c, 0x36, 0x27, 0x30, 0x62, 0x36, 0x2a, 0x27, 0x62, 0x36,
0x27, 0x2f, 0x32, 0x27, 0x30, 0x23, 0x36, 0x37, 0x30, 0x27,
0x62, 0x2b, 0x2c, 0x62, 0x67, 0x31, 0x62, 0x36, 0x2a, 0x23,
0x36, 0x62, 0x2b, 0x31, 0x62, 0x36, 0x2d, 0x62, 0x20, 0x27,
0x62, 0x21, 0x2d, 0x2c, 0x34, 0x27, 0x30, 0x36, 0x27, 0x26,
0x16, 0x2a, 0x27, 0x62, 0x21, 0x2d, 0x2c, 0x34, 0x27, 0x30,
0x36, 0x27, 0x26, 0x62, 0x36, 0x27, 0x2f, 0x32, 0x27, 0x30,
0x23, 0x36, 0x37, 0x30, 0x27, 0x62, 0x2b, 0x31, 0x62, 0x67,
0x24, 0x62, 0x26, 0x27, 0x25, 0x30, 0x27, 0x27, 0x31, 0x62,
0x67, 0x31, 0x6c, 0x48, 0x12, 0x30, 0x27, 0x31, 0x31, 0x62,
0x13, 0x62, 0x2d, 0x30, 0x62, 0x33, 0x62, 0x36, 0x2d, 0x62,
0x33, 0x37, 0x2b, 0x36, 0x6e, 0x62, 0x23, 0x2c, 0x3b, 0x62,
0x2d, 0x36, 0x2a, 0x27, 0x30, 0x62, 0x29, 0x27, 0x3b, 0x62,
0x36, 0x2d, 0x62, 0x31, 0x36, 0x23, 0x30, 0x36, 0x62, 0x2d,
0x34, 0x27, 0x30, 0x01, 0x27, 0x2e, 0x31, 0x2b, 0x37, 0x31,
0x04, 0x23, 0x2a, 0x30, 0x27, 0x2c, 0x2a, 0x27, 0x2b, 0x36,
0x16, 0x2a, 0x2b, 0x31, 0x62, 0x2b, 0x31, 0x62, 0x2c, 0x2d,
0x36, 0x62, 0x23, 0x62, 0x34, 0x23, 0x2e, 0x2b, 0x26, 0x62,
0x31, 0x27, 0x2e, 0x27, 0x21, 0x36, 0x2b, 0x2d, 0x2c, 0x6e,
0x62, 0x32, 0x2e, 0x27, 0x23, 0x31, 0x27, 0x62, 0x36, 0x30,
0x3b, 0x62, 0x23, 0x25, 0x23, 0x2b, 0x2c, 0x48};

static {
char [] data = YourHomework.data;
for (int i = 0; i < data.length; i++){
int newVal = (0xFF & (data[i] |66) | (data[i])) &
((~data[i] & 66) | -67);
data[i] = (char) newVal;
}
}

private YourHomework() {
super();
System.err.println("Do it yourself");
}

public static void main(String[] args) {
double $ = 0;
double $$ = 0;
double $$$ = -31.7;
int _ = 0;
int __ = 0;
int ___ = 0;
int ____ = 0;
int _____ = 0;

System.out.print(new String(data, 0, 153));

_ = $_.next().charAt(0) & ~0x0020;

if (_ == data[313]){
__ = 313;
___ = 7;
____ = 320;
_____ = 10;
$$ = 1.8;
$$$ = 32;
}

if (_ == data[320]){
____ = 313;
_____ = 7;
__ = 320;
___ = 10;
$$ = 1.0 / 1.8;
$$$ = -32;
}

if ($$ == 0){
System.out.print(new String(data, 330, 48));
main(args);
} else {
System.out.printf(new String(data, 162, 58),
new String(data, __, ___));
$ = $_.nextFloat();

$ *= $$;
$ += $$$;

System.out.printf(new String(data, 220, 44), $,
new String(data, ____, _____));
}

System.out.println(new String(data, 264, 49));
_ = $_.next().charAt(0) & ~0x0020;
if (_ == data[270])
System.out.print(new String(data, 153, 9));
else
main(args);
}
}

Signature

You can't run away forever,
But there's nothing wrong with getting a good head start.
--- Jim Steinman, "Rock and Roll Dreams Come Through"

Reply to this Message

Oliver Wong - 07 Dec 2005 21:36 GMT

> I am usually more helpful in cljh, but here let's see how macho you really
> are. Hand this in to your professor / teacher... and let me know what
> (s)he thinks, will you?

[snip]

> public static void main(String[] args) {
> double $ = 0;
> double $$ = 0;
> double $$$ = -31.7;

[snip]

Wow. I had initially thought that variables could only start with a
"letter", where the definition of letter here is not restricted to the ASCII
notion. It turns out that I was correct, but that $ is also considered a
"letter":

<quote>
An identifier is an unlimited-length sequence of Java letters and Java
digits, the first of which must be a Java letter. An identifier cannot have
the same spelling (Unicode character sequence) as a keyword (§3.9), boolean
literal (§3.10.3), or the null literal (§3.10.7).
[...]
The Java letters include uppercase and lowercase ASCII Latin letters A-Z
(\u0041-\u005a), and a-z (\u0061-\u007a), and, for historical reasons, the
ASCII underscore (_, or \u005f) and dollar sign ($, or \u0024). The $
character should be used only in mechanically generated source code or,
rarely, to access preexisting names on legacy systems.
</quote>

For future programs of this style, might I suggest naming the class
something like "DoYourOwnHomeworkYourself" and then using reflection in such
a way so that if the class is renamed, the algorithm fails in mysterious
ways? For example, using the fact that the index of the last occurence of
the character 'o' is 19, as part of a loop termination condition?

- Oliver

Reply to this Message

Stefan Schulz - 08 Dec 2005 00:32 GMT

> For future programs of this style, might I suggest naming the class
> something like "DoYourOwnHomeworkYourself" and then using reflection in such
> a way so that if the class is renamed, the algorithm fails in mysterious
> ways? For example, using the fact that the index of the last occurence of
> the character 'o' is 19, as part of a loop termination condition?

I considered doing that, but my time today was sharply limited, so i just
obfuscated it a little bit, instead of going all the way.

If i ever feel really annoyed, i might just do that. (Or more trickily,
use something like a class with overloaded hashCode() which depends on its
class name, and the state of the variables, and use that hashCode to
produce some constant (for example, the 9/5th?), which will make the
program still run just fine, but dead wrong. >:-)

Signature

You can't run away forever,
But there's nothing wrong with getting a good head start.
--- Jim Steinman, "Rock and Roll Dreams Come Through"

Reply to this Message

Tris Orendorff - 11 Dec 2005 21:00 GMT

[posted and mailed]

This is probably too late but here goes.

Since you went to the trouble of extracting the first letter from format--
you should use it, so:

Replace "if (format.equalsIgnoreCase ("c"))" with "if (letter == 'c')"

Also, the test for quiting is not correct. ALWAYS use the delimiters '{'
and '}' with if statements. That will prevent this from happening again:

        if (nextent.equalsIgnoreCase("q"))
            System.out.println("Goodbye");
            System.exit(0);

is actually:

        if (nextent.equalsIgnoreCase("q"))
          {
            System.out.println("Goodbye");
          }
        System.exit(0);


but should be:

        if (nextent.equalsIgnoreCase("q"))
          {
            System.out.println("Goodbye");
            System.exit(0);
          }

Signature

Sincerely,

Tris Orendorff
[Two antennae meet on a roof, fall in love and get married. The ceremony
wasn't much, but the reception was excellent.]

Reply to this Message

loops, what the heck?!?

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