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How to use base class's constructors and assignment operator in C++?
...
You can explicitly call constructors and assignment operators:
class Base {
//...
public:
Base(const Base&) { /*...*/ }
Base& operator=(const Base&) { /*...*/ }
};
class Derived : public Base
{
int additional_;
public:
Derived(const Derived& d)
: Base(d...
What is the point of a private pure virtual function?
... classes. Methods of derived classes can't call virtual functions from the base class, but they can provide their own implementation for them. According to Herb Sutter, having public non-virtual interface in the base class and a private implementation that can be customized in the derived classes, a...
The most efficient way to implement an integer based power function pow(int, int)
...
Exponentiation by squaring.
int ipow(int base, int exp)
{
int result = 1;
for (;;)
{
if (exp & 1)
result *= base;
exp >>= 1;
if (!exp)
break;
base *= base;
}
return result;
}
Th...
Calling virtual functions inside constructors
...om derived classes hasn’t yet happened. Objects are constructed from the base up, “base before derived”.
[...]
Destruction is done “derived class before base class”, so virtual functions behave as in constructors: Only the local definitions are used – and no calls are made to overriding ...
How to solve error “Missing `secret_key_base` for 'production' environment” (Rails 4.1)
...icorn.log file I found this error message:
app error: Missing `secret_key_base` for 'production' environment, set this value in `config/secrets.yml` (RuntimeError)
After some research I found out that Rails 4.1 changed the way to manage the secret_key, so if you read the secrets.yml file located ...
How can I specify the base for Math.log() in JavaScript?
I need a log function for JavaScript, but it needs to be base 10. I can't see any listing for this, so I'm assuming it's not possible. Are there any math wizards out there who know a solution for this?
...
Why does parseInt(1/0, 19) return 18?
...nfinity". So it works the same as if you asked it to convert "Infinity" in base 19 to decimal.
Here are the digits in base 19 along with their decimal values:
Base 19 Base 10 (decimal)
---------------------------
0 0
1 1
2 2
3 3
4 ...
Virtual/pure virtual explained
...han just the level at which it was created. Therefore if one method of the base class calls a virtual method, the version defined in the derived class will be used instead of the version defined in the base class.
This is in contrast to non-virtual functions, which can still be overridden in a der...
List all base classes in a hierarchy of given class?
... (whether it is a new-style class or not), how do you generate all the base classes - anywhere in the inheritance hierarchy - it issubclass of?
...
Is it possible to make abstract classes in Python?
...rties as using the abc module does. You can still instantiate the abstract base class itself, and you won't find your mistake until you call the abstract method at runtime.
But if you're dealing with a small set of simple classes, maybe with just a few abstract methods, this approach is a little e...