uintptr_t is an unsigned integer type that is capable of storing a data pointer. Which typically means that it’s the same size as a pointer. It is optionally defined in C++11 and later standards. A common reason to want an integer type that can hold an architecture’s pointer type is to perform integer-specific operations on a … Read more
When the compiler compiles the class User and gets to the MyMessageBox line, MyMessageBox has not yet been defined. The compiler has no idea MyMessageBox exists, so cannot understand the meaning of your class member. You need to make sure MyMessageBox is defined before you use it as a member. This is solved by reversing the definition order. However, you have a cyclic dependency: if you move MyMessageBox above User, … Read more
There is an operator missing, likely a *: The “is not callable” occurs because the parenthesis — and lack of operator which would have switched the parenthesis into precedence operators — make Python try to call the result of -3.7 (a float) as a function, which is not allowed. The parenthesis are also not needed in this case, the following may … Read more
To check if o is an instance of str or any subclass of str, use isinstance (this would be the “canonical” way): To check if the type of o is exactly str (exclude subclasses): The following also works, and can be useful in some cases: See Built-in Functions in the Python Library Reference for relevant information. One more note: in this case, if you’re using Python 2, you … Read more
Decimal datatype Unlike hardware based binary floating point, the decimal module has a user alterable precision (defaulting to 28 places) which can be as large as needed for a given problem. If you are pressed by performance issuses, have a look at GMPY
Decimal datatype Unlike hardware based binary floating point, the decimal module has a user alterable precision (defaulting to 28 places) which can be as large as needed for a given problem. If you are pressed by performance issuses, have a look at GMPY
You could use the BIT datatype to represent boolean data. A BIT field’s value is either 1, 0, or null.
DWORD is not a C++ type, it’s defined in <windows.h>. The reason is that DWORD has a specific range and format Windows functions rely on, so if you require that specific range use that type. (Or as they say “When in Rome, do as the Romans do.”) For you, that happens to correspond to unsigned int, but that might not … Read more
Possible Duplicate:What is “2’s Complement”? I know int32 has a length of 32 bits (4 bytes). I assume it has 2³² values but as half of them must be under zero, I guess it has something to do with this. I would like to know why exactly int32 has max. positive number 2³¹ − 1.
Nothing. will undergo autoboxing. The compiler replaces it with: You can see this if you decompile your class, e.g. using javap. Decompiles to: So how it is better initialize a variable, considering memory consumption and time complexity? Because they are semantically identical, the memory consumption and time complexity is also identical. Instead, focus on what is actually … Read more