03. Operators

연산자는 우선 순위를 가진다.

Arithmetic Operators

let a = 12
let b = 34

Unary Plus Operator

Example
+a

+a		// 12
+b 		// 34

Addition Operator

Example
a + b

a + b		// 46

Unary Minus Operator

Example
-a

-a		// -12
-b		// -34

Subtraction Operator

Example
a - b

a - b		// -32

Multiplication Operator

Example
a * b

a * b		// 408

Division Operator

Example
a / b

a / b		// 0
b / a		// 2

let c = Double(a)		// 12
let d = Double(b)		// 34

c / d		// 0.3529...
d / c		// 2.8333...

Remainder Operator (Modulo Operator)

나머지 값

Example
a % b

a % b
// c % d
c.truncatingRemainder(dividingBy: d)

Overflow

let num: Int = 9 * 9 * 9

Comparison Operatiors

let a = 12
let b = 34

Equal to Operator

Example
a == b

a == b		// false
"Swift" == "Swift"		// ture

Not equal to Operator

Example
a != b

a != b		// true

Greater than Operator

Example
a > b

a > b		// false
"swift" > "Swift"		// true

Greater than or equal to Operator

Example
a >= b

a >= b		// false
7 > 7		// false
7 >= 7		// true

Less than Operator

Example
a < b

a < b

Less than or equal to Operator

Example
a <= b

a <= b

Logical Operators

Logical NOT Operators

Example
!a

!true		// false
let a = 12
let b = 34

!(a < b)		// false

Logical AND Operators

Example
a && b

// 둘 다 조건이 만족할 때
a > 30 && b % 2 == 0		// fasle

true && true		// true
true && false		// false
false && false		// false

Logical OR Operators

a || b

```swift
// 둘 중 하나의 조건이 만족할 때
a > 30 || b % 2 == 0		// true

true || true		// true
true || false		// true
false || false		// false

Ternary Conditional Operator

Syntax
condition ? expr1 : expr2
조건 ? 성립1 : 성립2
조건이 true이면 성립1 호출
false면 성립2 호출

let hour = 12
// expr에 오는 자료형은 같아야함
hour  < 12 ? "am" : "pm"		// "pm"

if hour < 12{
    "am"
} else {
    "pm"		// "pm"
}

// hour < 11 "Good Morning"
// hour < 17 "Good Afternoon"
// "Good Evening"

hour < 11 ? "Good Morning" :
    (hour < 17 ? "Good Afternoon": "Good Evening")		// "Good Afternoon"

Assignment Operator

Assignment Operator

Example
a = b

let a = 12
var b = 34
b = a		// 12

Compound Assignment Operators

Addition Assignment Operator

Example
a += b
a = a + b

var a = 1
var b = 2
a = a + b		// 3

a = 1
b = 2
a += b			// 3

Subtraction Assignment Operator

Example
a -= b
a = a - b

a = 5
b = 3
a = a - b		// 2

a = 5
b = 3
a -= b			// 2

Multiplication Assignment Operator

Example
a = b
a = a b

a = 5
b = 3
a = a * b		// 15

a = 5
b = 3
a *= b			// 15

Division Assignment Operator

Example
a / = b
a = a / b

a = 7
b = 3
a = a/b		// 2

a = 7
b = 3
a /= b		// 2

Modulo Assignment Operator

Example
a %= b
a = a % b

a = 7
b = 3
a = a % b

a = 7
b = 3
a %= b

Range Operators

Closed Range Operator

Example
a...b
a...
...a

var sum = 0
for num in 1...10 {
	num
    sum += num
}
sum		// 55

let list = ["A", "B", "C", "D", "E"]
list [2...]		// ["C", "D", "E"]
list[...2]		// ["A", "B", "C"]

Half-Open Range Operator

Example
a ..< b
..< a

sum = 0
for num in 1..<10{
    sum += num
}
sum		// 45

list		// ["A", "B", "C", "D", "E"]
list[..<2]		// ["A", "B"]

let range = 0...5
range.contains(7)		// false
range.contains(3)  		// true