Every Java program (which is in turn, built up from one or more Java classes) requires a Main method. The purpose of this special method is to serve as an entry point to your program so that your program can be executed. More information can be found in this page. In your Pie example, what happens is that when … Read more
The answer, in a few words In your example, itsProblem is a local variable. Your must use self to set and get instance variables. You can set it in the __init__ method. Then your code would be: But if you want a true class variable, then use the class name directly: But be careful with this one, as theExample.itsProblem is automatically set to … Read more
JLS-8.3.1.1. static Fields says (in part) A static field, sometimes called a class variable, is incarnated when the class is initialized (§12.4). JLS-4.12.4. final Variables says (in part) A constant variable is a final variable of primitive type or type String that is initialized with a constant expression (§15.28) tl;dr Putting that together, a class constant is a static final field.
You could use my ancient Bunch recipe, but if you don’t want to make a “bunch class”, a very simple one already exists in Python — all functions can have arbitrary attributes (including lambda functions). So, the following works: Whether the loss of clarity compared to the venerable Bunch recipe is OK, is a style decision I will of … Read more
Creates an object of type Foo in dynamic memory. foo1 points to it. Normally, you wouldn’t use raw pointers in C++, but rather a smart pointer. If Foo was a POD-type, this would perform value-initialization (it doesn’t apply here). Identical to before, because Foo is not a POD type. Creates a Foo object called foo3 in automatic storage. Uses copy-initialization to create a Foo object called foo4 in automatic storage. Uses Bar‘s … Read more
A .class file is a compiled .java file. .java is all text and is human readable..class is binary (usually). You compile a java file into a class file by going to the command line, navigating to the .java file, and running You must have a java SDK installed on your computer (get it from Oracle), and … Read more
This is a linker error. Try: Basically, the linker is complaining about functions you used but didn’t provide an implementation for. To see all the steps the compiler performs for you, throw in a -v:
Suposse you have Class1 Class2 and then you can use Class2 in different ways. Class Field Method field Static methods from Class2 Imagine this is your class2. from class1 you can use doSomething from Class2 whenever you want
Try, This will work as long as you don’t use it in a static method.
In C#, there is a nice syntax sugar for fields with getter and setter. Moreover, I like the auto-implemented properties which allow me to write In C++ I have to write Is there some such concept in the C++11 allowing me to have some syntax sugar on this?