![]() ![]() There is a shortcut available with properties. We're going to set it equal to courseTitle. ![]() And it's courseTitle which is of String type. The parameters in the primary constructor are not visible to code outside of the class, however, we can use them to create class properties. And if we try to delete the word constructor now, we get a message telling us use constructor keyword after modifiers of the primary constructor. And what we're going to tell it is that we are going to make this one internal. And so here what we're going to do is do a little bit more cutting and pasting and we're going to call this Mandatoråonstructor. If you'd like to make the primary constructor callable only to code available internally in the same file, we add the internal visibility modifier to it which makes the keyword constructor necessary. Only when the constructor has an annotation or visibility modifier is the keyword constructor mandatory. Though we can say, call this one WithoutConstructor, and even though it does have a constructor, we can get rid of the constructor keyword. There is of course a shorter version since the constructor keyword is usually not mandatory. Constructor, and we say name, call a string and age colon int and some curly braces. It kind of looks like a functions parameter list. We define the primary constructor in the class header after its name with the keyword constructor and a list of names and types wrapped in parentheses. Kotlin has two kinds of class constructors creatively named primary and secondary. We use a classes constructor to pass data from the outside world into it. So we can all this one class ShortClass, and that's it. Just the keyword, class, and a name creates a perfectly legal class. We can create a class with an even shorter definition, but its usefulness is dubious. In Kotlin we only specify a visibility modifier if it isn't public. With each of then, the default is also public. We can apply visibility modifiers to the class's constructors, properties, and member functions. We change their visibility by adding private, protected, internal, or the redundant public before the class keyword. So let's create our own and then we're going to call it class. The definition begins with the keyword class, the name follows, and it finishes with a pair of curly braces. Classes are the primary way that we create data types. In object-oriented languages is like Kotlin. ![]()
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