identifier

问题 I'm using WMI in C++ classes to retrieve the serial number of my motherboard. The query is the following : "SELECT SerialNumber FROM Win32_BaseBoard" I wrote the query myself so i'm not certain it is correct, but it does return something : /9637CW1/CN1296131Q0BA8/ . The returned string is in the same format on multiple computers so i assume the query is correct. My question is : am i really querying the motherboard serial number here ? Because i saw another class called "Win32

问题 I have a snippet of code that looks like this: double Δt = lastPollTime - pollTime; double α = 1 - Math.exp(-Δt / τ); average += α * (x - average); Just how bad an idea is it to use unicode characters in Java identifiers? Or is this perfectly acceptable? 回答1: It's a bad idea, for various reasons. Many people's keyboards do not support these characters. If I were to maintain that code on a qwerty keyboard (or any other without Greek letters), I'd have to copy and paste those characters all the

问题 Are dollar-signs allowed in identifiers in C++03? covers that dollar signs in identifiers are not allowed in C++03. GCC provides it as a C extension and properly gives a diagnostic in C++03 mode. However, in C++11, int $ = 0 will compile without warning. This answer reasons that $ may be allowed because no diagnostic is required for implementation defined identifiers: The answer here is "Maybe" : According to §2.11 , identifiers may consist of digits and identifier-nondigits , starting with

问题 Are dollar-signs allowed in identifiers in C++03? covers that dollar signs in identifiers are not allowed in C++03. GCC provides it as a C extension and properly gives a diagnostic in C++03 mode. However, in C++11, int $ = 0 will compile without warning. This answer reasons that $ may be allowed because no diagnostic is required for implementation defined identifiers: The answer here is "Maybe" : According to §2.11 , identifiers may consist of digits and identifier-nondigits , starting with

问题 I just stumbled upon the following odd situation: >>> class Test: µ = 'foo' >>> Test.µ 'foo' >>> getattr(Test, 'µ') Traceback (most recent call last): File "<pyshell#4>", line 1, in <module> getattr(Test, 'µ') AttributeError: type object 'Test' has no attribute 'µ' >>> 'µ'.encode(), dir(Test)[-1].encode() (b'\xc2\xb5', b'\xce\xbc') The character I entered is always the µ sign on the keyboard, but for some reason it gets converted. Why does this happen? 回答1: There are two different characters

问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 7 years ago . I decided to program an iphone app to see how easy it was. I have finalized most of the coding except this part, please help: #import

问题 I create all the variables within the same function. But at the end of the function I can't reach the constant even though it was created in the same function. When I write "self.resultLabel.text = weather" at the end, Xcode shows me an error use of unresolved identifier 'weather' I know how to fix it. I need to initiate 'weather' just after the task method starts and set it to "" and then I should change its value in the function but even if I don't do it and I create it in the if closures,

问题 I need my C program to be able to read in an identifier using the scanf() method in C. An identifier in this case is a letter or a _ character followed by one or more alphanumeric characters including the _ character. The regular expression would be [a-ZA-Z_][a-zA-Z0-9_]* These are examples of correct identifiers: _identifier1 variable21 These are examples of incorrect identifiers 12var %foobar Does anybody know how this would be done using scanf() in C? 回答1: scanf() doesn't support regular

问题 I have a problem with the drawable class in R.java file. I had drawable hdpi, mdpi, xhdpi... folders in main/res, but drawable was missing so i created it by hand. Main.xml is able to find the image declared but this code in R.java gives an error: public static final class drawable { public static final int 10_device_access_accounts=0x7f020000; public static final int 10_device_access_add_alarm=0x7f020001; public static final int 10_device_access_alarms=0x7f020002; public static final int 10

问题 This is a small part of a grammer using expressions. prefix = (lit(L"not") >> prefix) |(lit('-') >> prefix) | postfix ; Some way inside postfix I have name_pure to take an identifier .. name_pure = lexeme[+(boost::spirit::standard_wide::alpha | '_') >> *(boost::spirit::standard_wide::alnum | '_')]; So far all is fine. Can write something like a=not b But if I start to use not as a name prefix like this one a=not notvarname I get a parser Output from the AST which look like this a=not not