下面是一段javabean 程序，该程序的运行结果是 （ ） 。public class NullTest{public static void main(String[] args){int M = 0;String str = null;StringBuffer sb = new StringBuffer(“= “);sb.append(str);sb.append(M++);System.out.println(sb.toString());}}
A: =null
B: =null0
C: =null1
D: =nullM
A: =null
B: =null0
C: =null1
D: =nullM
举一反三
- 5、下列程序的运行结果是（）。public static void main( String[] args ){StringBuffer sb = new StringBuffer();sb.append("qq").append("ww");show( sb, "ss" );System.out.println( sb.length() );}public void show( StringBuffer sb, String str ){sb.append( str );} A: 4 B: 2 C: 6 D: 0
- public class Example { String str = new String("Java"); StringBuffer sb = new StringBuffer("C#"); public void strcat(String str, StringBuffer sb) { str = str + " study"; sb = sb.append(" exam"); } public static void main(String args[]) { Example ex = new Example(); ex.strcat(ex.str, ex.sb); System.out.println(ex.str); System.out.println(ex.sb); }}程序的输出结果是：______
- 分析下面的Java程序段,编译运行后的输出结果是( )。public class Test {public void changeString(StringBuffer sb) {sb.append("stringbuffer2");}public static void main(String[] args) {Test a = new Test();StringBuffer sb = new StringBuffer("stringbuffer1");a.changeString(sb);System.out.println("sb = " + sb);}} A: sb = stringbuffer2stringbuffer1 B: sb = stringbuffer1 C: sb = stringbuffer2 D: sb = stringbuffer1stringbuffer2
- class Test { public static void main(String[] args) { StringBuffer sb = new StringBuffer("jack"); sb.append(true); sb.append('a'); sb.append(97).append(34.0).append(new char[]{'A','B'}); // 链式编程 System.out.println( sb.toString() ); // 输出缓冲区的中文本数据 sb = new StringBuffer("jack"); sb.insert( 2, "java" ); System.out.println( sb.toString() ); } } A: jacktruea9734.0AB jjavaack B: jacktruea9734.0AB jajavack C: jacktrueaa34.0AB jajavack D: jacktruea9734AB jajavack
- 下列程序的运行结果是（）public class Test {public static void main(String[] args) {String str = NULL;System.out.println(str);}} A: