JAVA1 - 6 데이터와 연산

public class Main {
    public static void main(String[] args) {
        System.out.println(6); //Number
        System.out.println("six"); //String

        System.out.println("6"); //String 6

        System.out.println(6*6); //36
        //System.out.println("6"*"6"); Error

        System.out.println("1111".length()); //4
        //System.out.println(1111.length()); Error 숫자는 길이x
    }
}

public class Main {
    public static void main(String[] args) {
        System.out.println(Math.PI); ///3.141592653589793
        System.out.println(Math.floor(Math.PI));/// 3.0  floor:내림
        System.out.println(Math.ceil(Math.PI));////4.0   ceil:올림
    }
}

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello World"); //String 문자열
        System.out.println('H'); // Character 문자
        System.out.println("H");

        System.out.println("Hello " +
                "World"); /// Hello World 줄바꿈 안 됨.
        System.out.println("Hello \nWorld"); //줄바꿈 성공. 역슬래쉬 내 자판에서 원화표시
    }
}

 

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello World"); //String 문자열
        System.out.println('H'); // Character 문자
        System.out.println("H");

        System.out.println("Hello " +
                "World"); /// Hello World 줄바꿈 안 됨.
        System.out.println("Hello \nWorld"); //줄바꿈 성공. 역슬래쉬 내 자판에서 원화표시
        System.out.println("hello \"World\""); ///hello "World" 
    }
}

줄바꿈 역슬래쉬   \n

역슬래쉬를 통해서 임무가 있는 문자열의 역할을 탈출, 해방시키는 것. escape

 

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello World".length()); //11
        System.out.println("Hell, [[[name]]]...bye.".replace("[[[name]]]","egoing"));
    }
}

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello World".length()); //11
        System.out.println("Hell, leezche...bye.".replace("leezche","egoing"));
    }
}