Java语言程序设计与数据结构》编程练习答案（第二十一章）（二）

《Java语言程序设计与数据结构》编程练习答案（第二十一章）（二）

英文名：Introduction to Java Programming and Data Structures, Comprehensive Version, 11th Edition

21.8

public class book {


    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        HashMap<String, Integer> map = new HashMap<>();
        System.out.println("enter the xxx");
        String xxx = input.nextLine();
        String[] words = xxx.split("[\\s,\\,,\\;,\\.,\\:,\\?,\\(,\\),\',\"]");
        for (String word : words) {
            String key = word.toLowerCase();
            if (map.containsKey(key)) {
                int occur = map.get(key);
                occur++;
                map.put(key, occur);
            } else {
                map.put(key, 1);
            }
        }

        for(Map.Entry<String, Integer> entry: map.entrySet()){
            System.out.println(entry.getValue()+"\t"+entry.getKey());
        }
    }
}

21.9

public class book {


    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        HashMap<String, String> provinces = new HashMap<>();
        provinces.put("Liaoning","Shenyang");
        provinces.put("Jilin","Changchun");
        provinces.put("Heilongjiang","Ha'erbin");

        System.out.println("Please enter a name of a province:");
        String pName = input.nextLine();
        if(provinces.containsKey(pName)){
            System.out.println("The capital of "+pName+" is "+provinces.get(pName));
        }
        else{
            System.out.println("Please enter a valid province name");
        }
    }
}

21.10

public class book {


    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        HashMap<String, Integer> keyWords = new HashMap<>();
        keyWords.put("int",0);
        keyWords.put("double",0);
        System.out.println("enter the code");
        boolean valid = true;
        while(input.hasNext()){
            String word = input.next();
            if(word.equals("//")){
                valid = false;
            }else if(word.equals("\n")){
                valid = true;
            }else if(word.equals("\"")){
                valid = !valid;
            }else{
                if(keyWords.containsKey(word)){
                    int occur = keyWords.get(word);
                    occur++;
                    keyWords.put(word, occur);
                }
            }
        }

    }
}

21.11

public class book {


    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        ArrayList<HashMap<String, Integer>> boyRank = new ArrayList<>(10);
        //HashMap[] girlRank = new HashMap[10];
        for(int i=0;i<10;i++){
            boyRank.add(new HashMap<String, Integer>());
        }
        boyRank.get(0).put("Tom",1);
        boyRank.get(0).put("Jerry",2);
        boyRank.get(1).put("Jerry",1);
        boyRank.get(1).put("Tom",2);
        System.out.println("Please enter the year:");
        int year = input.nextInt();
        System.out.println("Please enter the name:");
        String name = input.nextLine();
        name = input.nextLine();
        System.out.println("The rank is "+boyRank.get(year).get(name));


    }
}

21.12

有、想了。

21.14

public class book {


    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        ArrayList<HashMap<String, Integer>> boyRank = new ArrayList<>(10);
        //HashMap[] girlRank = new HashMap[10];
        for(int i=0;i<10;i++){
            boyRank.add(new HashMap<String, Integer>());
        }
        boyRank.get(0).put("Tom",1);
        boyRank.get(0).put("Jerry",2);
        boyRank.get(1).put("Jerry",1);
        boyRank.get(1).put("Tom",2);
        while(true) {
            System.out.println("Please enter the year:");
            int year = input.nextInt();
            System.out.println("Please enter the name:");
            String name = input.nextLine();
            name = input.nextLine();
            System.out.println("The rank is " + boyRank.get(year).get(name));
            System.out.println("Enter another query?");
            String another = input.nextLine();
            if(another.equals("N")){
                break;
            }
        }


    }
}

21.14

爬

21.15

忘了

第二十一章 完