[멀티캠퍼스] interface, abstract, 설명
import java.util.*; import java.io.*; class 수업내용 { public static void main(String [] a) { String str = "Hello World"; boolean b = str.equals( "Hello World"); System.out.println( b ); int len = str.length( ); System.out.println( len ); char c = str.charAt(0); System.out.println( c ); for( int i = 0 ; i < str.length( ) ; i++) { System.out.print( str.charAt( i ) ); } System.out.println( ); } } /* p..