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浅析为什么char类型的范围是 -128~+127 - C/C++ - 清泛网 - 专注C/C++及内核技术
...减法，它会转化为1+(-1) ,因此
0000 0001
+ 1000 0001
____________________
1000 0010 …………… -2 ，1-1= -2? 这显然是不对了，所以为了避免减法运算错误，计算机大神们发明出了反码，直接用最高位表示符号位的叫做...
Object of custom type as dictionary key
...
You need to add 2 methods, note __hash__ and __eq__:
class MyThing:
def __init__(self,name,location,length):
self.name = name
self.location = location
self.length = length
def __hash__(self):
return hash((self.name...
javac not working in windows command prompt
...
ah yes, all i had to do was re-open the command prompt and it worked fine, thanks!
– Domenic
Nov 5 '09 at 6:02
1
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Polymorphism in C++
...ecific code selected?
Run time means the compiler must generate code for all the types the program might handle while running, and at run-time the correct code is selected (virtual dispatch)
Compile time means the choice of type-specific code is made during compilation. A consequence of this: say...
How does BLAS get such extreme performance?
...e optimization. This boost significantly exceeds the second boost from parallelism and other hardware optimizations.
By the way, most (or even all) of the high performance BLAS implementations are NOT implemented in Fortran. ATLAS is implemented in C. GotoBLAS/OpenBLAS is implemented in C and i...
Regex lookahead, lookbehind and atomic groups
...ely follow, and stop as backtracking is disabled
A non-atomic group will allow backtracking; if subsequent matching ahead fails, it will backtrack and use alternative patterns until a match for the entire expression is found or all possibilities are exhausted.
(foo|foot)s applied to foots will:
...
Why do you need explicitly have the “self” argument in a Python method?
... to make things like this explicit rather than based on a rule.
Additionally, since nothing is implied or assumed, parts of the implementation are exposed. self.__class__, self.__dict__ and other "internal" structures are available in an obvious way.
...
Simple Log to File example for django 1.3+
...ogfile'],
'level': 'DEBUG',
},
}
}
Now what does all of this mean?
Formaters I like it to come out as the same style as ./manage.py runserver
Handlers - I want two logs - a debug text file, and an info console. This allows me to really dig in (if needed) and look at a te...
How is __eq__ handled in Python and in what order?
...
The a == b expression invokes A.__eq__, since it exists. Its code includes self.value == other. Since int's don't know how to compare themselves to B's, Python tries invoking B.__eq__ to see if it knows how to compare itself to an int.
If you amend your ...
What version of Visual Studio is Python on my computer compiled with?
...to be Visual C++ 2008 according to this thread on the OpenCobol forums (of all places).
The MSDN page on Predefined Macros indicates 1500 to be the result of the _MSC_VER macro.
This other forum post mentions that
(For reference, Visual Studio 2003 has _MSC_VER = 1310; Visual Studio 2005 ha...