1일차(o t) //Hello World

8bit = = 1 byte

 

0~255

8bit

1kbyte = =1024 byte

1m byte = = 1024 k  byte

1 g byte = = 1024 m byte5                                    

 

 

1. code 작성

2. compile (언어 -> 기계어)

3. build (실행파일을 작성)

-외부파일

4. link

5. execute

계속동작중 실시간으로 

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public class MainClass {       public static void main(String[] args) {         //주석문 : 설명 기입 가능 , 컴파일이 되지 않는다. 명시하는 문자열                  /*         //범위 주석문          코드를 설명할때 많이 사용           Oracle --          Html <!-- -->          JSP <%-- --%>          python """          # 한줄 주석문                    언어: c, java, objective-C, python          C언어: 함수(function), 절차지향          java: class, ( object ) 객체지향                    절차지향 : 1 ->2 ->3 //순서대로 진행된다          객체지향 : 순서를 중시하지 않고 각종처리 중심, 1,2,3 - > 처리                             출력output, 입력 input          입력 input - > 계산(computer) ->출력output                    println 행바꿈          print 행바꿈x         */         System.out.println("Hello World");         System.out.print("Hello");         System.out.print("World");                  System.out.println();// 개행                  System.out.println("World");                  System.out.println("한"); // " " - > 두개이상의 문자 -> 문자열         System.out.println('한'); // ' ' - > 한개의 문자         System.out.println('문' + "자열");                  System.out.println("123" + "4");         System.out.println(123 + 5 +"4");         System.out.println(123 + 5 +"4");         System.out.println("123"+ 5 + 4);                           //printf         System.out.printf("%c %d %f %s",'A', 12, 123.456, "hello");                  //escape sequence         // \n \t \" \' \b         System.out.print("\n hello \n");         System.out.print("world\n");         System.out.println("hi\nhello\nworld");         System.out.println("hi\thello\tworld");              System.out.println("\"홍길동\"입니다"); //따옴표 표시         System.out.println("'홍길동'입니다"); //따옴표 표시              }   }   Colored by Color Scripter

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Hello World HelloWorld World 한 한 문자열 1234 1284 1284 12354 A 12 123.456000 hello  hello  world hi hello world hi    hello    world "홍길동"입니다 '홍길동'입니다

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