超星 - 字符串与数组小测 - 查题吧

单选题

已知String s = "www.qypt.com.cn"; 下面哪个语句是不合法的?

A. int len = s.length;
B. s = s + 100;
C. s += "books";
D. String t = s + "true";

单选题

已知:String s = "ABCD1234";int a=s.indexOf("123",3);int b=s.lastIndexOf("123",3);则a、b的值分别为

A. 4,4
B. 4,-1
C. -1,4
D. -1,-1

单选题

已知:String s = "AB12ab12";String s1= s.replace("12","CD");String s2= s.replaceAll("12","CD");则s1、s2的值分别为:

ABCDab12, ABCDabCD
B. ABCDabCD, ABCDab12
C. AB12abCD, ABCDab12
D. ABCDabCD, ABCDabCD

单选题

已知String s1 = "ABCD1234"; String s2="abcd1234"; 下面结果为true的是

A. s1==s2;
B. s1.equals(s2);
C. s1. equalsIgnoreCase (s2);
D. s1.compareTo(s2);

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