Fahrenheit <=> Celsius Converter

[Joe]

http://www.javaop.com/uploads/guest/FCConverter.tar.gz

It's more of an example of how to do this than anything. Plus it shows how to use the Java tool line to create javadocs (and cut them down to only what you need), run the java disassembler (and stick it in a file), and of course, compile. Shell script included to do that stuff.

EDIT -
Replaced assembler with disassembler (hehe, oops).

[rabbit]

F?

[Joe]

Fahrenheit

[Sidoh]

No Kelvins? :(

[Ergot]

No Kelvins? :(

Just add 273 to Celcius :\

[Sidoh]

Just add 273 to Celcius :\

I know. : - P

I want his program to do it for me.

[Joe]

It's open source for a reason! <3.

[MyndFyre]

No Kelvins? :(

Just add 273 to Celcius :\

273.15

It's open source for a reason! <3.

And that reason is?

[Joe]

And that reason is?

You're kidding, right? To show others how I did it, and for Sigh-dough to add his nice modification. ^_^

[Sidoh]

x86] link=topic=5504.msg64307#msg64307 date=1144613172]
273.15

Depends on significant digits and desired accuracy. ;)

[deadly7]

Is it me or does this seem like a really basic thing to make?

[MyndFyre]

Is it me or does this seem like a really basic thing to make?

z0mG N00es!  J00 gotta get teh 1nput, m4ke 1t a num|3er, times and add teh numb3rz, n put 1t on t3h scr33nz.  c0mp|_icated!!!!!!1!1!11!1!one11!

[Quik]

Is it me or does this seem like a really basic thing to make?

In most "learn to program" books, this is the 2nd or 3rd program it has you make. Complexity is not the point here, not even usefulness (though I can see a situation where someone might find it handy). The point is that he's practicing programming and (supposedly) learning new things.

From your comment, I take it you can make this same program in a quick 5 minutes? Thought so.

[MyndFyre]

The point is that he's practicing programming and (supposedly) learning new things.

I might say that he's not.  He's still doing typical Joe things.  For instance:

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if ((args.length == 0) || (args.length == 1))

How about:

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if (args.length < 2)

so that we only need one runtime check if args.length == 1?

Then he's got this:

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System.out.println(args[1] + " F = " + fToC(Double.parseDouble(args[1])) + " C.");

...which is not the most readable thing ever.  Not exactly the most beneficial for him learning or someone else learning.

Then he has inconsistent accessibility which is shown in his JavaDoc:

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public static double fToC(double temp)
private static double cToF(double temp)

An external user trying to convert Celsius to Fahrenheit will get a compile-time error because cToF is private.

Finally, his algorithms are just wrong:

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/**
Converts a temperature from fahrenheit to celsius
@param temp Temperature to convert (fahrenheit)
@return Converted temperature (celsius)
*/
public static double fToC(double temp)
{
return 100.0 / 212 * (temp - 32.0);
}

/**
Converts a temperature from celsius to fahrenheit
@param temp Temperature to convert (celsius)
@return Converted temperature (fahrenheit)
*/
private static double cToF(double temp)
{
return 212.0 / 100 * temp + 32.0;
}

It's well-known that the appropriate formulae for converting between Celsius and Fahrenheit are the following:
C to F: degreesC * 9 / 5 + 32
F to C: (degreesF - 32) * 5 / 9

For example, when converting 10 C to Fahrenheit, Joe's program would return 53.2 F, where the correct value is actually 50 F. 

Also, it is commonly known that the Fahrenheit and Celsius scales intersect at -40 degrees.  Joe's algorithms, however, return the following:
-40 C to F: -52.8
-40 F to C: -33.96

Ultimately this is a completely and utterly worthless "tutorial," with the exception that it shows that you should use .equalsIgnoreCase when you're parsing command-line arguments.

[deadly7]

Is it me or does this seem like a really basic thing to make?

In most "learn to program" books, this is the 2nd or 3rd program it has you make. Complexity is not the point here, not even usefulness (though I can see a situation where someone might find it handy). The point is that he's practicing programming and (supposedly) learning new things.

From your comment, I take it you can make this same program in a quick 5 minutes? Thought so.

Uh.  Joe boasts about his programming knowledge, and unless he picked up a new language I doubt this is learning something new for him.

I don't program.  Programming bores me.