논리 연산자와 단락 평가

let isWeekend = true
let isSunny = false
print(isWeekend && isSunny)
print(isWeekend || isSunny)
print(!isSunny)

let loggedIn = false
if !loggedIn {
    print("Please log in")
}

let hasTicket = true
let hasID = true
let canEnter = hasTicket && hasID
print("Can enter:", canEnter)

let isAdmin = false
let isOwner = true
let canEdit = isAdmin || isOwner
print("Can edit:", canEdit)

let age = 20
let hasGuardian = false
let allowed = (age >= 18) || hasGuardian
print("Allowed:", allowed)

func sideEffect() -> Bool {
    print("sideEffect ran")
    return true
}
let result = false && sideEffect()
print("Result:", result)

func sideEffect() -> Bool {
    print("sideEffect ran")
    return false
}
let result = true || sideEffect()
print("Result:", result)

let numbers = [10, 20, 30]
let index = 5
if index < numbers.count && numbers[index] > 0 {
    print("Safe access")
} else {
    print("Index out of bounds guarded")
}

func check(_ label: String, _ value: Bool) -> Bool {
    print("checking", label)
    return value
}
let r = check("A", false) && check("B", true)
print("Final:", r)

let temp = 25
let humidity = 40
let comfortable = (temp >= 18 && temp <= 26) && (humidity < 60)
print("Comfortable:", comfortable)

let a = true
let b = false
print(!(a && b))
print(!a || !b)

let list = [1, 2, 3]
let i = 10
let safe = i < list.count && list[i] == 2
print("Safe and matched:", safe)