java编程思想第四版第十三章字符串 习题

时间：2023-03-09 00:54:06
java编程思想第四版第十三章字符串 习题
  1. fas
  2. 第二题 
    package net.mindview.strings;

import java.util.ArrayList;
    
import java.util.List;

/**
    
 * 无限循环
    
 */
    
public class InfiniteRecursion {
    
    public InfiniteRecursion(){

    }
    
    @Override
    
    public String toString() {
    
        return " InfiniteRecursion address" + super.toString() + "\n";
    
    }
    
    public static void main(String[] args) {
    
        List<InfiniteRecursion> list = new ArrayList<InfiniteRecursion>();
    
        for(int i=; i<; i++){
    
            list.add(new InfiniteRecursion());
    
        }
    
        System.out.println(list);
    
    }
    
}
  3. fa
  4. 第四题 
    package net.mindview.strings;

import java.util.Formatter;

public class Receipt {
    
    private double total = ;
    
    private Formatter f = new Formatter(System.out);
    
    public final int ITEM_WIDTH = ;
    
    public final int QTY_WIDTH = ;
    
    public final int PRICE_WIDTH = ;
    
    public final int PRICISION_FLOAT_WIDHT = ;
    
    public final int PRICISION_String_WIDHT = ;
    
    public final String TITLE_FORMAT = "%-" + ITEM_WIDTH + "s %" + QTY_WIDTH
    
            + "s %" + PRICE_WIDTH + "s\n";
    
    public final String PRICE_FORMAT = "%-" + ITEM_WIDTH + "."
    
            + PRICISION_String_WIDHT + "s %" + QTY_WIDTH + "d %" + PRICE_WIDTH
    
            + "." + PRICISION_FLOAT_WIDHT + "f\n";
    
    public final String TOTAL_FORMAT = "%-" + ITEM_WIDTH + "s %" + QTY_WIDTH
    
            + "s %" + PRICE_WIDTH + "." + PRICISION_FLOAT_WIDHT + "f\n"; 

    //打印标题
    
    public void printTitle(){
    
        /*
    
         * 含义: 格式化字符串串以%开头
    
         * -: 表示左对齐
    
         * 15: 15表示宽度
    
         * s:表示数据的类型是String
    
         * .2f:表示浮点数保留的小数位数
    
         * .15s:表示字符串的长度最多15个字符
    
         */
    
        f.format(TITLE_FORMAT, "Item", "Qty", "Price");
    
        f.format(TITLE_FORMAT, "----", "---", "-----");
    
    }

    //正文的内容
    
    public void print(String name, int qty, double price){
    
        f.format(PRICE_FORMAT, name, qty, price);
    
        total += price;
    
    }

    //总价
    
    public void printTotal(){
    
        f.format(TOTAL_FORMAT, "Tax", "", total*0.06);
    
        f.format(TITLE_FORMAT, "", "", "-----");
    
        f.format(TOTAL_FORMAT, "Total", "", total*1.06);
    
    }

    public static void main(String[] args) {
    
        Receipt receipt = new Receipt();
    
        receipt.printTitle();
    
        receipt.print("Jack`s Magic Beans", , 4.25);
    
        receipt.print("Princess Peas", , 5.1);
    
        receipt.print("Three Bears Porridge", , 14.29);
    
        receipt.printTotal();
    
    }

}

    运行结果：

    Item              Qty      Price
    
----              ---      -----
    
Jack`s Magic Be            4.25
    
Princess Peas              5.10
    
Three Bears Por           14.29
    
Tax                         1.42
    
                           -----
    
Total                      25.06
  5. 第五题 
    package net.mindview.strings;

import java.util.Formatter;

public class Receipt {
    
    private double total = ;
    
    private Formatter f = new Formatter(System.out);
    
    public final int ITEM_WIDTH = ;
    
    public final int QTY_WIDTH = ;
    
    public final int PRICE_WIDTH = ;
    
    public final int PRICISION_FLOAT_WIDHT = ;
    
    public final int PRICISION_String_WIDHT = ;
    
    public final String TITLE_FORMAT = "%-" + ITEM_WIDTH + "s %" + QTY_WIDTH
    
            + "s %" + PRICE_WIDTH + "s\n";
    
    public final String PRICE_FORMAT = "%-" + ITEM_WIDTH + "."
    
            + PRICISION_String_WIDHT + "s %" + QTY_WIDTH + "d %" + PRICE_WIDTH
    
            + "." + PRICISION_FLOAT_WIDHT + "f\n";
    
    public final String TOTAL_FORMAT = "%-" + ITEM_WIDTH + "s %" + QTY_WIDTH
    
            + "s %" + PRICE_WIDTH + "." + PRICISION_FLOAT_WIDHT + "f\n"; 

    //打印标题
    
    public void printTitle(){
    
        /*
    
         * 含义: 格式化字符串串以%开头
    
         * -: 表示左对齐
    
         * 15: 15表示宽度
    
         * s:表示数据的类型是String
    
         * .2f:表示浮点数保留的小数位数
    
         * .15s:表示字符串的长度最多15个字符
    
         */
    
        f.format(TITLE_FORMAT, "Item", "Qty", "Price");
    
        f.format(TITLE_FORMAT, "----", "---", "-----");
    
    }

    //正文的内容
    
    public void print(String name, int qty, double price){
    
        f.format(PRICE_FORMAT, name, qty, price);
    
        total += price;
    
    }

    //总价
    
    public void printTotal(){
    
        f.format(TOTAL_FORMAT, "Tax", "", total*0.06);
    
        f.format(TITLE_FORMAT, "", "", "-----");
    
        f.format(TOTAL_FORMAT, "Total", "", total*1.06);
    
    }

    public static void main(String[] args) {
    
        Receipt receipt = new Receipt();
    
        receipt.printTitle();
    
        receipt.print("Jack`s Magic Beans", , 4.25);
    
        receipt.print("Princess Peas", , 5.1);
    
        receipt.print("Three Bears Porridge", , 14.29);
    
        receipt.printTotal();
    
    }

}

    运行结果:

    Item              Qty      Price
    
----              ---      -----
    
Jack`s Magic Be            4.25
    
Princess Peas              5.10
    
Three Bears Por           14.29
    
Tax                         1.42
    
                           -----
    
Total                      25.06
  6. afd
  7. 第七题: 
    package net.mindview.strings.test7;

public class Test7 {

    public static void main(String[] args) {
    
        //两种写法都可以
    
        String regex = "^[A-Z].*\\.$";
    
        String regex1 = "\\p{Upper}.*\\.$";
    
        String str = "D.";
    
        String str1 = "Dfasdfasfasfdasfdasfasfasdf.";
    
        String str2 = "Dfasdfasfasfdasfdasfasfasdf.E";
    
        System.out.println(str.matches(regex));
    
        System.out.println(str1.matches(regex));
    
        System.out.println(str2.matches(regex));
    
        System.out.println(str.matches(regex1));
    
        System.out.println(str1.matches(regex1));
    
        System.out.println(str2.matches(regex1));
    
    }
    
}

    运行结果:

    true
    
true
    
false
    
true
    
true
    
false
  8. 第八题 
    package net.mindview.strings;

import java.util.Arrays;

public class Splitting {

    public static String knights = "Then, when you have found the shrubbery, you must cut down the mightiest tree in the forest... with... a herring!";

    public static void split(String regex){
    
        System.out.println(Arrays.toString(knights.split(regex)));
    
    }
    
    public static void main(String[] args) {
    
        //表示的时按照空格分割字符串
    
        //运行结果:[Then,, when, you, have, found, the, shrubbery,, you, must, cut, down, the, mightiest, tree, in, the, forest..., with..., a, herring!]
    
        split(" ");

        //表示按照非单次字符分割字符串--这里的非单次字符是空格和,
    
        //运行结果:[Then, when, you, have, found, the, shrubbery, you, must, cut, down, the, mightiest, tree, in, the, forest, with, a, herring]
    
        split("\\W+");
    
        //这个表示:费单次字符之前带n的地方进行分割字符串 这里的分割符是n空格和n,
    
        //运行结果:[The, whe, you have found the shrubbery, you must cut dow, the mightiest tree i, the forest... with... a herring!]
    
        split("n\\W+");
    
    }

}
    package net.mindview.strings.test8;

import net.mindview.strings.Splitting;

public class Test8 {

    public static void main(String[] args) {
    
        String regex = "the|you";
    
        Splitting.split(regex);
    
    }
    
}
  9. 第九题 
    package net.mindview.strings.test9;

import net.mindview.strings.Splitting;

public class Test9 {
    
    public static void main(String[] args) {
    
        String regex = "A|E|I|O|U|a|e|i|o|u";
    
        //通过嵌入式标志表达式  (?i) 也可以启用不区分大小写的匹配。
    
        String regex1 = "(?i)a|e|i|o|u";
    
        //[abc] 表示a或b或c
    
        String regex2 = "(?i)[aeiou]";
    
        System.out.println(Splitting.knights.replaceAll(regex, "_"));
    
        System.out.println(Splitting.knights.replaceAll(regex1, "_"));
    
        System.out.println(Splitting.knights.replaceAll(regex2, "_"));
    
    }
    
}
  10. 第十题 
    package net.mindview.strings.test10;

import java.util.regex.Matcher;
    
import java.util.regex.Pattern;

public class Test10 {
    
    public static void main(String[] args) {
    
        String str = "Java now has regular expressions";

        for(String arg: args){
    
            Pattern p = Pattern.compile(arg);
    
            Matcher m = p.matcher(str);
    
            while(m.find()){
    
                System.out.println("Match \"" + m.group() +"\" at positions " + m.start() + "-" + (m.end()-) );
    
            }
    
            System.out.println("\n");
    
        }

    }
    
}

    输入参数:

    ^Java
    
\Breg.*
    
n.w\s+h(a|i)s
    
s?
    
s*
    
s+
    
s{}
    
s{}.
    
s{,}

    输出结果

    Match "Java" at positions -

Match "now has" at positions -

Match "" at positions --
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "s" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "s" at positions -
    
Match "s" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "s" at positions -
    
Match "" at positions -

Match "s" at positions -
    
Match "ss" at positions -
    
Match "s" at positions -

Match "s " at positions -
    
Match "ss" at positions -

Match "" at positions --
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "s" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "ss" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "" at positions -
    
Match "s" at positions -
    
Match "" at positions -
  11. 第十一题 
    package net.mindview.strings.test11;

import java.util.regex.Matcher;
    
import java.util.regex.Pattern;

public class Test11 {
    
    public static void main(String[] args) {
    
        Pattern p = Pattern.compile("(?i)((^[aeiou])|(\\s+[aeiou]))\\w+?[aeiou]\\b");
    
        Matcher m = p.matcher("Arline ate eight apples and " +
    
"one orange while Anita hadn't any");

        while(m.find()){
    
            System.out.println("Match \"" + m.group() +
    
                    "\" at positions " + m.start() + "-" +
    
                    (m.end() - ));
    
        }
    
    }
    
}

    运行结果:

    Match "Arline" at positions -
    
Match " ate" at positions -
    
Match " one" at positions -
    
Match " orange" at positions -
    
Match " Anita" at positions -
  12. sfa
  13. f
  14. a
  15. fda
  16. sdf
  17. af
  18. a
  19. fd
  20. af
  21. as
  22. fd
  23. asfd
  24. af
  25. da
  26. f
  27. df
  28. as
  29. fa
  30. sf
  31. asf
  32. a
  33. sf
  34. af
  35. asf

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