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return nil

}

}

}

let circname = rectangle()

circname.print?[ 0 ] = radius(radiusname: "Diameter")

let printing = circle()

printing.area.append(radius(radiusname: "Units"))

printing.area.append(radius(radiusname: "Meter"))

circname.print = printing

var area = ["Radius": [ 35 , 45 , 78 , 101 ], "Circle": [ 90 , 45 , 56 ]]

area["Radius"]?[ 1 ] = 78

area["Circle"]?[ 1 ]--

println(area["Radius"]?[ 0 ])

println(area["Radius"]?[ 1 ])

println(area["Radius"]?[ 2 ])

println(area["Radius"]?[ 3 ])

println(area["Circle"]?[ 0 ])

println(area["Circle"]?[ 1 ])

println(area["Circle"]?[ 2 ])

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

Optional(35)

Optional(78)

Optional(78)

Optional(101)

Optional(90)

Optional(44)

Optional(56)