一、选择题
1、下面哪些是java语言中的关键字? A sizeof B abstract C NULL D Native 答:B
2、下面语句哪个是正确的? A char='abc'; B long l=oxfff; C float f=0.23; D double=0.7E-3; 答:D
3、以下程序测试String 类的各种构造方法,试选出其运行效果。
public class abc {
public static void main(String args[]){
String s1=new String();
String s2=new String("String 2");
char chars[]={'a',' ','s','t','r','i','n','g'};
String s3=new String(chars);
String s4=new String(chars,2,6);
byte bytes[]={0,1,2,3,4,5,6,7,8,9};
StringBuffer sb = new StringBuffer(s3);
String s5=new String(sb);
System.out.println("The String No.1 is "+s1);
System.out.println("The String No.2 is "+s2);
System.out.println("The String No.3 is "+s3);
System.out.println("The String No.4 is "+s4);
System.out.println("The String No.5 is "+s5);
}
}
A The String No.1 is
The String No.2 is String 2
The String No.3 is a string
The String No.4 is string
The String No.5 is a string
B The String No.1 is The String No.2 is String 2 The String No.3 is a string
The String No.4 is tring The String No.5 is a string
C The String No.1 is The String No.2 is String 2 The String No.3 is a string
The String No.4 is strin The String No.5 is a string
D 以上都不对
答:A
4、下面语句段的输出结果是什么?
inti = 9; switch (i) {
default: System.out.println("default");
case 0: System.out.println("zero"); break;
case 1: System.out.println("one");
case 2: System.out.println("two"); }
A default
B default, zero
C error default clause not defined
D no output displayed
答:B
二、不定项选择题(在每小题的五个备选答案中选出正确答案,并将正确答案的序号填入题干后面的括号内,错选多选,漏选均不得分。)
1、给出如下代码:
class Test{ private int m; public static void fun() { // some code... } } 如何使成员变量m 被函数fun()直接访问?
A、将private int m 改为protected int m B、将private int m 改为 public int m
C、将private int m 改为 static int m D、将private int m 改为int m
答: C
2、下面哪几个函数是public void example(){...}的重载函数?
A、 public void example( int m){...} B、public int example(){...}
C、public void example2(){...} D、 public int example ( int m, float f){...}
答: A,D