kotlin var and val

Kotlin provides two keywords for declaring variables: var and val.

var is used to declare a mutable variable, which means its value can be changed after it is initialized. Here's an example:

var name: String = "John"
name = "Mike" // Valid, the value of name can be changed

In this example, the variable name is declared using var and assigned an initial value of "John". Later, the value of name is changed to "Mike", which is allowed because name is mutable.

On the other hand, val is used to declare an immutable variable, which means its value cannot be changed once it is assigned. Here's an example:

val age: Int = 25
age = 30 // Invalid, the value of age cannot be changed

In this example, the variable age is declared using val and assigned an initial value of 25. Later, attempting to change the value of age to 30 results in an error because age is immutable.

To summarize, var is used for mutable variables, allowing their values to be changed, while val is used for immutable variables, preventing their values from being changed after initialization.