Swift Tutorial - Tutorialspoint

let sa = [

Chemistry(physics: "solid physics", equations: "Hertz"),

Maths(physics: "Fluid Dynamics", formulae: "Giga Hertz")]

let samplechem = Chemistry(physics: "solid physics", equations: "Hertz")

println("Instance physics is: \(samplechem.physics)")

println("Instance equation is: \(samplechem.equations)")

let samplemaths = Maths(physics: "Fluid Dynamics", formulae: "Giga Hertz")

println("Instance physics is: \(samplemaths.physics)")

println("Instance formulae is: \(samplemaths.formulae)")

When we run the above program using playground, we get the following result:

Instance physics is: solid physics

Instance equation is: Hertz

Instance physics is: Fluid Dynamics

Instance formulae is: Giga Hertz

Type Checking

Type checking is done with the 'is' operator. The 'is' type check operator checks whether
the instance belongs to particular subclass type and returns 'true' if it belongs to that
instance else it will return 'false'.

class Subjects {

var physics: String

init(physics: String) {

self.physics = physics

}

}

class Chemistry: Subjects {

var equations: String

init(physics: String, equations: String) {