java编程思想第四版第十三章字符串 习题

2023-07-29 20:06:22

  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=0; i<5; 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 = 0;
    private Formatter f = new Formatter(System.out);
    public final int ITEM_WIDTH = 15;
    public final int QTY_WIDTH = 5;
    public final int PRICE_WIDTH = 10;
    public final int PRICISION_FLOAT_WIDHT = 2;
    public final int PRICISION_String_WIDHT = 15;
    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, 4.25);
        receipt.print("Princess Peas", 3, 5.1);
        receipt.print("Three Bears Porridge", 1, 14.29);
        receipt.printTotal();
    }

}

    运行结果：

    Item              Qty      Price
----              ---      -----
Jack`s Magic Be     4       4.25
Princess Peas       3       5.10
Three Bears Por     1      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 = 0;
    private Formatter f = new Formatter(System.out);
    public final int ITEM_WIDTH = 15;
    public final int QTY_WIDTH = 5;
    public final int PRICE_WIDTH = 10;
    public final int PRICISION_FLOAT_WIDHT = 2;
    public final int PRICISION_String_WIDHT = 15;
    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, 4.25);
        receipt.print("Princess Peas", 3, 5.1);
        receipt.print("Three Bears Porridge", 1, 14.29);
        receipt.printTotal();
    }

}

    运行结果:

    Item              Qty      Price
----              ---      -----
Jack`s Magic Be     4       4.25
Princess Peas       3       5.10
Three Bears Por     1      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()-1) );
            }
            System.out.println("\n");
        }
        
    }
}

    输入参数:

    ^Java
\Breg.*
n.w\s+h(a|i)s
s?
s*
s+
s{4}
s{1}.
s{0,3}

    输出结果

    Match "Java" at positions 0-3




Match "now has" at positions 5-11


Match "" at positions 0--1
Match "" at positions 1-0
Match "" at positions 2-1
Match "" at positions 3-2
Match "" at positions 4-3
Match "" at positions 5-4
Match "" at positions 6-5
Match "" at positions 7-6
Match "" at positions 8-7
Match "" at positions 9-8
Match "" at positions 10-9
Match "s" at positions 11-11
Match "" at positions 12-11
Match "" at positions 13-12
Match "" at positions 14-13
Match "" at positions 15-14
Match "" at positions 16-15
Match "" at positions 17-16
Match "" at positions 18-17
Match "" at positions 19-18
Match "" at positions 20-19
Match "" at positions 21-20
Match "" at positions 22-21
Match "" at positions 23-22
Match "" at positions 24-23
Match "" at positions 25-24
Match "s" at positions 26-26
Match "s" at positions 27-27
Match "" at positions 28-27
Match "" at positions 29-28
Match "" at positions 30-29
Match "s" at positions 31-31
Match "" at positions 32-31




Match "s" at positions 11-11
Match "ss" at positions 26-27
Match "s" at positions 31-31




Match "s " at positions 11-12
Match "ss" at positions 26-27


Match "" at positions 0--1
Match "" at positions 1-0
Match "" at positions 2-1
Match "" at positions 3-2
Match "" at positions 4-3
Match "" at positions 5-4
Match "" at positions 6-5
Match "" at positions 7-6
Match "" at positions 8-7
Match "" at positions 9-8
Match "" at positions 10-9
Match "s" at positions 11-11
Match "" at positions 12-11
Match "" at positions 13-12
Match "" at positions 14-13
Match "" at positions 15-14
Match "" at positions 16-15
Match "" at positions 17-16
Match "" at positions 18-17
Match "" at positions 19-18
Match "" at positions 20-19
Match "" at positions 21-20
Match "" at positions 22-21
Match "" at positions 23-22
Match "" at positions 24-23
Match "" at positions 25-24
Match "ss" at positions 26-27
Match "" at positions 28-27
Match "" at positions 29-28
Match "" at positions 30-29
Match "s" at positions 31-31
Match "" at positions 32-31

     

  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() - 1));
        }
    }
}

    运行结果:

    Match "Arline" at positions 0-5
Match " ate" at positions 6-9
Match " one" at positions 27-30
Match " orange" at positions 31-37
Match " Anita" at positions 44-49

     

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