How do I get System.out.format to print out doubles with the same precision

Question

Using the System.out.format, how do I print out the value of a double such that it looks exactly like it does if it were print from a System.out.println.
For example, take the following code:
double d = 12.48564734342343;       
System.out.format("d as format: %f\n", d);
System.out.println("d as   sout: " + d);Running the code, I get:
<font face="courier">
d as format: 12.485647
d as sout: 12.48564734342343
</font>
The precision of d has been lost.
I could bump up the precision as follows:
double d = 12.48564734342343;
System.out.format("d as format: %.14f\n", d);
System.out.println("d as   sout: " + d);That appears to work, I get:
<font face="courier">
d as format: 12.48564734342343
d as sout: 12.48564734342343
</font>
However, that solution fails if d has a different precision, say 12.48. In that case I get:
<font face="courier">
d as format: 12.48000000000000
d as sout: 12.48
</font>
So how do I get System.out.format to print out doubles with the same precision as System.out.println?
Thanks..

Answer 1

YoungWinston wrote:
Schmoe wrote:
Interesting, but this is not what I am looking for...Your original question was "how do I print out the value of a double such that it looks exactly like it does if it were print from a System.out.println", and you've been told how to do that (although the pattern given by sabre may be a bit excessive - you should only need 15 '#'s).The initial phrase from my question was "Using the System.out.format, how do I..".
It's worth remembering that, unlike the Format hierarchy, 'format()' is NOT native to Java. It's a convenience implementation of the 'printf()' and 'sprintf()' methods provided in C, and first appeared in Java 1.5. Those methods were designed to produced fixed-format output; 'println()' was not.Perhaps it is the case that this can't be done.
Furthermore, Double.toString(), which is what is used by println() does not produce the same format in all cases; format("%.14f\n", d) does. TrySystem.out.println(1.8236473845783d);
System.out.println(1823647384.5783d);and you'll see what I mean.I am fine with that. It still displays all the precision.
I am simply looking for a way to quickly print out multiple variables on a sysout while debugging. I want it as syntactically sweet as possible. System.out.println can be a pain when outputting multiple variables like the following:
"System.out.println("a: " + a + "; b:" + b + "; c: " + c);"
For some reason, my fingers always typo the plus key.
I was hoping that System.out.format would be easier,along the lines of:
"System.out.format("a: %f, b: %f, c: %f\n", a, b, c);"
From a syntactical sweetness point of view, it is easier. However, the %f on doubles truncates the precision. I figured there must be a way to get the full precision.
DecimalFormat is syntactically sour for this purpose, as you need to instantiate the DecimalFormat.
fwiw I have enjoyed reading the suggestions in this thread...