선언 + let first = "Hello, " let second = "world" let greeting = first + second 더블 쿼테이션 let quote = "Then he tapped a sign saying \"Believe\" and walked away." 문자열에 다른 변수를 포함 let name = "Taylor" let age = 26 let message = "Hello, my name is \(name) and I'm \(age) years old." print(message) * \(변수) : 값이 아니라 변수자체를 참조 print("5 x 5 is \(5 * 5)") 숫자를 문자로 변환 let number = 11 let missionMessage = "Apollo ..