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String, text, numbers, I/O II part<br />
Check out the % (modulus) operator, it computes the remainder.<br />
public int modMethod(int div){<br />
if(div%2==0){<br />
return 1;<br />
} else{<br />
return 0;<br />
}<br />
}<br />
Q: How can I round a number to specified precision?<br />
I have a double field that I would like to round to 2 places of precision, however, it<br />
seems like the documentation on the round function only rounds to<br />
closest integers. So that I would not be able say .3658585859 = .37 as<br />
I would like.<br />
Answer: can you scale the number up and then down again when you are finished?<br />
e.g. 0.3658585859 * 100 = 36.58585859<br />
round(36.58585859) = 37<br />
37 / 100 = 0.37<br />
I understand that bitwise operations change the 0/1 bits of a number. Question is<br />
why?<br />
I suppose it's interesting that you can manipulate numbers this way, but I can't think<br />
of a practical use for doing that.<br />
Can anyone help me understand when are bitwise operations used and why you<br />
would use them?<br />
Answer: Bitwise manipulation is often used where memory consumption is critical,<br />
and a piece of information may be encoded in less that one byte, for instance. In<br />
communication software and protocols, information may be interpreted as a stream<br />
of bits where the information is encoded at the bit-level, and you use bitwise<br />
manipulation to extract the pieces of information encoded in the bytes. There are<br />
other situations where bitwise manipulation is used, as well.<br />
by Greger Ohlson<br />
Why cannot I cast from double to java.lang.Object?<br />
Q: I'm trying to build a vector, however, one of the objects that I'm passing to the<br />
vector is of type double. How do I cast the double as an object so that I may insert<br />
the value into a vector? Does this make sense? Here is the following snippet of code<br />
I was trying to use:<br />
myVector.add (1, (Object)myDouble);<br />
Of course when I try to compile I get the following message:<br />
Invalid cast from double to java.lang.Object<br />
Could someone please explain why? I realize that Object is the mother of all objects<br />
and therefore ANY reference data type "is an" Object. So therefore I shouldn't have<br />
to cast the double, right? Help, I'm a beginner!<br />
Answer: A double is not a reference type, but a primitive one. Hence, it doesn't<br />
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