What is tailRec in Kotlin?

tailrec optimizes functions where there is tail recursion. You don't have to mark the method as having tail recursion. The compiler just notices that the last operation is recursive. And that's that.

Also question is, what does fun mean in Kotlin?

Functions are the basic building block of any program. In Kotlin functions are declared with the fun keyword and they are first-class citizen. It means that functions can be assigned to the variables, passed as an arguments or returned from another function.

Similarly, what is with in Kotlin? with() is not an extension function on type T, but it takes a instance of T as the first argument. Also Kotlin allows us to move the last function argument out of the parenthesis. block is defined as T. () -> R so you don't have to use it , and you can change the return value in block body.

Similarly one may ask, what is args in Kotlin?

Kotlin Default Argument In Kotlin, you can provide default values to parameters in function definition. If the function is called with arguments passed, those arguments are used as parameters. However, if the function is called without passing argument(s), default argument are used.

Can we pass a different number of arguments to the same function in Kotlin?

Kotlin provides us to achieve the same by defining a parameter of a function as vararg . We can pass n number of parameters to a vararg variable of the defined datatype or even of a generic type. If the size of n variables is not fixed, we usually convert it into an array or list and pass it to function.

Is keyword in Kotlin?

TypeCheck ('is') and Cast ('as') in Kotlin. Type check is a way of checking the type( DataType ) or Class of a particular instance or variable while runtime to separate the flow for different objects. In few languages, it's also denoted as Run Time Type Identification (RTTI) .

What is the meaning of in Kotlin?

Kotlin is a static type, object-oriented programing (OOP) language that is interoperable with the Java virtual machine, Java libraries and Android. Kotlin focuses on stripped down, functional code and avoids repetitive "boilerplate" code. The language features null safety, eliminating null pointer exception errors.

How do I return a null in Kotlin?

In Kotlin, there are optional types. If you return ServiceChargeMasterList, you say to the compiler that you will never return null. If you want to return null, you have to add ? sign at the end of the type which indicates that you can return an instance of ServiceChargeMasterList or null.

How do you write Kotlin?

Android Studio fully supports Kotlin, enabling you to create new projects with Kotlin files, add Kotlin files to your existing project, and convert Java language code to Kotlin.

Add Kotlin into an existing app

1. Start by writing tests in Kotlin.
2. Write new code in Kotlin.
3. Update existing code to Kotlin.

What does -> mean in Kotlin?

The -> is a separator. It is special symbol used to separate code with different purposes. It can be used to: Separate the parameters and body of a lambda expression val sum = { x: Int, y: Int -> x + y } Separate the parameters and return type declaration in a function type (R, T) -> R.

What does string mean in Kotlin?

A string is a basic data type in a programming language. In Kotlin, the String class represents character strings. Kotlin string literals are implemented as instances of this class. Kotlin/Java strings are immutable, which means that all modification operations create new string instead of modifying a string in-place.

How do you declare int in Kotlin?

In Kotlin, use val to declare a constant or var keywords to declare a variable. You can specify a type such as String or Int after the variable name. In the example below, we declared a constant firstName of type String with the val keyword.

How do I return a value to Kotlin?

Kotlin has three structural jump expressions:

1. return. By default returns from the nearest enclosing function or anonymous function.
2. break. Terminates the nearest enclosing loop.
3. continue. Proceeds to the next step of the nearest enclosing loop.

What is varargs in java?

Varargs is a short name for variable arguments. In Java, an argument of a method can accept arbitrary number of values. This argument that can accept variable number of values is called varargs.

What is Java Kotlin?

Kotlin is a general purpose, free, open source, statically typed “pragmatic” programming language initially designed for the JVM (Java Virtual Machine) and Android that combines object-oriented and functional programming features. It is focused on interoperability, safety, clarity, and tooling support.

How do you pass parameters in Kotlin?

You can pass a variable number of arguments to a function by declaring the function with a vararg parameter. In Kotlin, a vararg parameter of type T is internally represented as an array of type T ( Array<T> ) inside the function body.

Can when statement in kotlin be used without passing any argument?

Instead the Kotlin's when can offer much more than that:

• it can be used as an expression or a statement (i.e., it can return a value or not)
• it has a better and safer design.
• it can have arbitrary condition expressions.
• it can be used without an argument.

How do I create a data class in Kotlin?

Kotlin Data Class Requirements

1. The primary constructor must have at least one parameter.
2. The parameters of the primary constructor must be marked as either val (read-only) or var (read-write).
3. The class cannot be open, abstract, inner or sealed.
4. The class may extend other classes or implement interfaces.

How do you use a loop in Kotlin?

There is no traditional for loop in Kotlin unlike Java and other languages. In Kotlin, for loop is used to iterate through ranges, arrays, maps and so on (anything that provides an iterator).

How do you use Elvis operator Kotlin?

Basically, if the left side of Elvis returns null for some reason, returns the right side instead. i.e. So, if number is NOT null, it will print number, otherwise will print "Number is null". The elvis operator in Kotlin is used for null safety.

How do I create an array in Kotlin?

There are two ways to define an array in Kotlin. We can use the library function arrayOf() to create an array by passing the values of the elements to the function. Since Array is a class in Kotlin, we can also use the Array constructor to create an array.

What is inline function in Kotlin?

Inline Function. An inline function is declare with a keyword inline. The use of inline function enhances the performance of higher order function. The inline function tells the compiler to copy parameters and functions to the call site. The virtual function or local function cannot be declared as inline.