java2实用教程(第三版)第五章习题答案(耿祥义).doc

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1、publicclassT5_1{publicstaticvoidmain(String[]args){//已定义好的字符串变量Strings="HelloWorld!";System.out.println(s);s=s.toUpperCase();System.out.println(s);s=s.toLowerCase();System.out.println(s);//通过键盘输入字符串/*System.out.println(args[0]);args[0]=args[0].toUpperCase();Sys

2、tem.out.println(args[0]);args[0]=args[0].toLowerCase();System.out.println(args[0]);*/}}publicclassT5_2{publicstaticvoidmain(String[]args){//通过键盘输入两个字符串,在java时注意在敲入javaStringCat时在后面加上两个字符串。eg.javaStringCat"Hello""China";/*System.out.println("string1:"+args[0]);S

3、ystem.out.println("string2:"+args[1]);args[0]=args[0].concat(args[1]);System.out.println("concatstring:"+args[0]);*///已定义的字符串Strings1="Hello";Strings2="China!";System.out.println("s1="+s1);System.out.println("s2="+s2);s1=s1.concat(s2);System.out.println("concat

4、....");System.out.println("s1="+s1);System.out.println("s2="+s2);}}publicclassT5_3{publicstaticvoidmain(String[]args){Strings="中国科学技术大学";chara=s.charAt(2),b=s.charAt(6);System.out.print(a);System.out.println(b);}}importjava.util.*;publicclassT5_4{publicstaticvo

5、idmain(String[]args){int[]a={23,67,89,90,-987};double[]b={12.89,90.87,34,678.987,-98.78,0.89};Arrays.sort(a);Arrays.sort(b,1,4);for(inti=0;i<=4;i++){System.out.print(a[i]+",");}System.out.println();for(inti=0;i

6、ut.println();}}publicclassT5_5{publicstaticvoidmain(String[]args){char[]a1={'a','b','c','d','e','f'},b1={'1','2','3','4','5','6'};System.arraycopy(a1,0,b1,1,a1.length-1);System.out.println(newString(a1));System.out.println(newString(b1));byte[]a2={97,98,99,100,

7、101,102},b2={65,67,68,69,70,71};System.arraycopy(b2,0,a2,3,b2.length-3);System.out.println(newString(a2));System.out.println(newString(b2));}}