Hands-On Object-Oriented Programming with Kotlin

The var keyword

The var keyword declares a mutable property or local variable. This means that the variable can be changed or updated as follows during the course of the entire program:

var age = 25

In the preceding code, var is a keyword, age is a variable name, and 25 is an assigned integer value. Let's see some other variable definitions to understand the declarations better:

• var myChar = 'A': myChar is a single character variable
• var name = "Bob": A name is a string type variable
• var age = 10: age is an integer type variable
• var height = 5.10: height is a double type variable

In Kotlin, a variable must have a value assigned. Without proper initialization, it does not allow variable declarations:

var age //In-Valid Declaration; compiler ...