Swift Programming Examples

Variadic Parameters

swift

func vari<N>(members: N...){
   for i in members {
      print(i)
   }
}

vari(members: 4,3,5)
vari(members: 4.5, 3.1, 5.6)
vari(members: "Swift 4", "Enumerations", "Closures")

External Parameter Names

swift

func pow(firstArg a: Int, secondArg b: Int) -> Int {
   var res = a
   for _ in 1..<b {
      res = res * a
   }
   print(res)
   return res
}

pow(firstArg:5, secondArg:3)

Local Parameter Names

swift

func sample(number: Int) {
   print(number)
}

sample(number: 1)
sample(number: 2)
sample(number: 3)

Functions with Optional Return Types

swift

func minMax(array: [Int]) -> (min: Int, max: Int)? {
   if array.isEmpty { return nil }
   var currentMin = array[0]
   var currentMax = array[0]
   
   for value in array[1..<array.count] {
      if value < currentMin {
         currentMin = value
      } else if value > currentMax {
         currentMax = value
      }
   }
   return (currentMin, currentMax)
}

if let bounds = minMax(array: [8, -6, 2, 109, 3, 71]) {
   print("min is \(bounds.min) and max is \(bounds.max)")
}

Functions without Return Values

swift

func sum(a: Int, b: Int) {
   let a = a + b
   let b = a - b
   print(a, b)
}

sum(a: 20, b: 10)
sum(a: 40, b: 10)
sum(a: 24, b: 6)

Functions with Return Values

swift

func ls(array: [Int]) -> (large: Int, small: Int) {
   var lar = array[0]
   var sma = array[0]

   for i in array[1..<array.count] {
      if i < sma {
         sma = i
      } else if i > lar {
         lar = i
      }
   }
   return (lar, sma)
}

let num = ls(array: [40,12,-5,78,98])
print("Largest number is: \(num.large) and smallest number is: \(num.small)")

Functions without Parameters

swift

func votersname() -> String {
   return "Alice"
}
print(votersname())

Functions with Parameters

swift

func mult(no1: Int, no2: Int) -> Int {
   return no1*no2
}

print(mult(no1: 2, no2: 20))
print(mult(no1: 3, no2: 15))
print(mult(no1: 4, no2: 30))

Calling a Function

swift

func display(no1: Int) -> Int {
   let a = no1
   return a
}

print(display(no1: 100))
print(display(no1: 200))

Function Program

swift

func student(name: String) -> String {
   return name
}

print(student(name: "First Program"))
print(student(name: "About Functions"))

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