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这篇文章主要讲解了“如何使用swift函数”，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习“如何使用swift函数”吧！
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func greet(_ person: String = "zhang san", _ hometown: String = "bei jing") -> String {
return "Hello \(person)! Glad you could visit from \(hometown)"
}
print(greet())
//Hello zhang san! Glad you could visit from bei jing//不定参数个数
func sum(_ nums: Int...) -> Int {
var ret = 0
for n in nums {
ret += n
}
return ret
}
print(sum(1,2,3))
//6
print(sum(1,2,3,4,5))
//15//函数内改变函数外定义的参数值
func swap(_ a: inout Int, _ b: inout Int) {
let temp = a
a = b
b = temp
}
var a = 1
var b = 2
swap(&a, &b)
print(a)
//2
print(b)
//1func add(_ a: Int, _ b: Int) -> Int {
return a + b
}
var addFunc: (Int, Int) -> Int = add
print(addFunc(1, 2))
//3func printResult(_ f: (Int, Int) -> Int, _ a: Int, _ b: Int) {
print("Result: \(f(a, b))")
}
printResult(add, 1,2)
//Result: 3func forward(_ input: Int) -> Int {
return input + 1
}
func backward(_ input: Int) -> Int {
return input - 1
}
func step(isBack: Bool) -> (Int) -> Int {
return isBack ? backward : forward
}
//记数倒数到0
var currValue = 3
let moveNearerToZero = step(isBack: currValue > 0)
print("Counting to zero:")
while currValue != 0 {
print("\(currValue)...")
currValue = moveNearerToZero(currValue)
}
print("zero!")
/*
Counting to zero:
3...
2...
1...
zero!
*/func chooseStepFunc(backward: Bool) -> (Int) -> Int {
func stepForward(input: Int) -> Int {
return input + 1
}
func stepBackward(input: Int) -> Int {
return input - 1
}
return backward ? stepBackward : stepForward
}
print("Counting to zero:")
var cVal = -4
let toZero = chooseStepFunc(backward: cVal > 0)
while cVal != 0 {
print("\(cVal)...")
cVal = toZero(cVal)
}
print("zero!")
/*
Counting to zero:
-4...
-3...
-2...
-1...
zero!
*/感谢各位的阅读，以上就是“如何使用swift函数”的内容了，经过本文的学习后，相信大家对如何使用swift函数这一问题有了更深刻的体会，具体使用情况还需要大家实践验证。这里是创新互联，小编将为大家推送更多相关知识点的文章，欢迎关注！