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Android Development with Kotlin by Igor Wojda, Marcin Moskala

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Type inference

As we saw in previous examples, unlike Java, the Kotlin type is defined after variable name:

    var title: String 

At first glance, this may look strange to Java developers, but this construct is a building block of a very important feature of Kotlin called type inference. Type inference means that the compiler can infer type from context (the value of an expression assigned to a variable). When variable declaration and initialization is performed together (single line), we can omit the type declaration. Let's look at the following variable definition:

    var title: String = "Kotlin" 

The type of the title variable is String, but do we really need an implicit type declaration to determine variable type? On the right side of the ...

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