One reason certainly is because it doesn’t hurt. One reason where it’s needed is, if you have default arguments for the first parameter. The constructor becomes a default constructor, but can still be used as converting constructor struct A { explicit A(int = 0); // added it to a default constructor }; C++0x makes actual … Read more
This declares an explicit default constructor: struct A { explicit A(int a1 = 0); }; A a = 0; /* not allowed */ A b; /* allowed */ A c(0); /* allowed */ In case there is no parameter, like in the following example, the explicit is redundant. struct A { /* explicit is redundant. … Read more
Reading explanation of members : explicit char_separator(const Char* dropped_delims, const Char* kept_delims = “”, empty_token_policy empty_tokens = drop_empty_tokens) explicit char_separator() The explicit keyword for the 1st constructor requires explicit creation of objects of char_separator type. What does the explicit keyword mean in C++? covers the explicit keyword very well. The explicit keyword for the 2nd … Read more
When you explicitly implement the interface, you first have to cast the object to the interface, then you can call the method. In other words, the method is only available when the method is invoked on the object as the interface type, not as the concrete type. class Vehicle: IVehicle { public int IVehicle.getWheel() { … Read more
The traditional wisdom is that constructors taking one parameter (explicitly or effectively through the use of default parameters) should be marked explicit, unless they do define a conversion (std::string being convertible from const char* being one example of the latter). You’ve figured out the reasons yourself, in that implicit conversions can indeed make life harder … Read more
This declares an explicit default constructor: struct A { explicit A(int a1 = 0); }; A a = 0; /* not allowed */ A b; /* allowed */ A c(0); /* allowed */ In case there is no parameter, like in the following example, the explicit is redundant. struct A { /* explicit is redundant. … Read more
No, you can’t use explicit, but you can use a templated function to catch the incorrect parameter types. With C++11, you can declare the templated function as deleted. Here is a simple example: #include <iostream> struct Thing { void Foo(int value) { std::cout << “Foo: value” << std::endl; } template <typename T> void Foo(T value) … Read more
The implicit and explicit keywords in C# are used when declaring conversion operators. Let’s say that you have the following class: public class Role { public string Name { get; set; } } If you want to create a new Role and assign a Name to it, you will typically do it like this: Role … Read more
Yes and No. It depends on which version of C++, you’re using. C++98 and C++03 do not support explicit type conversion operators But C++11 does. Example, struct A { //implicit conversion to int operator int() { return 100; } //explicit conversion to std::string explicit operator std::string() { return “explicit”; } }; int main() { A … Read more
The rows you get back from iterrows are copies that are no longer connected to the original data frame, so edits don’t change your dataframe. Thankfully, because each item you get back from iterrows contains the current index, you can use that to access and edit the relevant row of the dataframe: for index, row … Read more