七、泛型

func swapTwoInts(_ a:inout Int, _ b:inout Int) {
    let temp = a
    a = b
    b = temp
}

func swaoTwoValues<T>(_ a:inout T, _ b:inout T) {
    let temp = a
    a = b
    b = temp
}

var a = 13, b = 12
swapTwoInts(&a, &b)
print(a, b)

var aStr = "12", bStr = "333"
//swapTwoInts(&aStr, &bStr)

swaoTwoValues(&a, &b)
print(a, b)
swaoTwoValues(&aStr, &bStr)
print(aStr, bStr)
// 上面的