Advanced Programming-Week15

仅供学习交流，请勿复制粘贴用于提交作业！

Summary

1.  文件类 File
   1. Scanner 的初始化
   2. PrintWriter 类
2. 数组列表 ArrayList

Task84

package Week15;

import java.util.*;

public class Task84
{
    public static char[] remove(char []arr,int n)
    {
        char t=' ';
        for(int i=0;i<n;i++)
        {
            t=arr[arr.length-1];
            for(int j=arr.length-1;j>0;j--)
            {
                arr[j]=arr[j-1];
            }
            arr[0]=t;
        }
        return arr;
    }

    public static char[] input()
    {
        Scanner in= new Scanner(System.in);
        String s=in.nextLine();
        char []arr=s.toCharArray();
        // in.close();
        return arr;
    }
    public static void main(String[] args)
    {
        Scanner in= new Scanner(System.in);
        char []arr=input();
        int n=in.nextInt();
        in.close();
        int len=arr.length;
        n=n%len;
        arr=remove(arr,n);
        for(int i=0;i<arr.length;i++)
        {
            System.out.print(arr[i]);
        }
        in.close();
    }
}

The vote

import java.util.*;
import java.io.*;

public class vote {

    public static void input(ArrayList<String> BandList,String BandNumber)throws Exception
    {
        File file = new File(BandNumber);
        String BandInfo="";
        if(file.exists())
        {
            Scanner in = new Scanner(file);
            while(in.hasNextLine())
            {
                BandList.add(in.nextLine());
            }
        }else{
            System.out.println("not found");
        }
    }

    public static int votes() throws Exception
    {
        int []voteCount=new int[1000];
        Scanner in = new Scanner(System.in);
        while(in.hasNext())
        {
            int i=Integer.parseInt(in.next());
            voteCount[i]++;
        }
        int maxCount = -1;
        int flag=-1;
        for(int i=0;i<voteCount.length;i++)
        {
            if(voteCount[i]>maxCount)
            {
                maxCount = voteCount[i];
                flag=i;
            }
        }
        return flag;
    }

    public static void output(ArrayList<String> BandList,int winer,String Votes)throws Exception
    {
        String []inforList=new String[2];
        for(String i:BandList)
        {
            inforList=i.split(",");
            int tag=Integer.parseInt(inforList[0]);
            if(winer==tag)
            {
                PrintWriter out=new PrintWriter(Votes);
                out.println(inforList[1]);
                out.close();
                return;
            }
        }
    }
    public static void main(String []args)throws Exception
    {
        String BandNumber="BandNumber.txt";
        String Votes="votes.txt";
        ArrayList<String> BandList = new ArrayList<String>();
        input(BandList,BandNumber);
        int winer=votes();
        output(BandList,winer,Votes);
    }
}

The delete

package Week15.delete;

import java.util.*;
import java.io.*;
import java.util.regex.*;

public class delete {
    public static void delete(String filename,String Id)throws Exception
    {
        File file= new File(filename);
        Scanner in= new Scanner(file);
        ArrayList<String>content=new ArrayList<String>();
        String temp="";
        
        Pattern pattern=Pattern.compile(Id);
        Matcher matcher=pattern.matcher("");

        if(file.exists())
        {
            while(in.hasNext())
            {
                temp=in.nextLine();
                matcher=pattern.matcher(temp);
                if(!matcher.find())
                {
                    content.add(temp);
                }
            }
        }
        PrintWriter out = new PrintWriter(filename);
        for(var i:content)
        {
            out.println(i);
        }
        out.close();
    }
    public static void main(String []args)throws Exception
    {
        String filename="Week15/delete/classList.txt";
        String Id="CS4092";
        delete(filename,Id);
    }
}

The merge

package Week15.merge;
import java.util.*;
import java.io.*;

public class merge {
    public static void input(TreeSet<String> dataSet, String filename1,String filename2) throws IOException {
        File file1 = new File(filename1);
        File file2 = new File(filename2);

        if(file1.exists())
        {
            Scanner in1= new Scanner(file1);
            while(in1.hasNext())
            {
                dataSet.add(in1.next());
            }
        }
        if(file2.exists())
        {
            Scanner in2= new Scanner(file2);
            while(in2.hasNext())
            {
                dataSet.add(in2.next());
            }
        }
    } 
    public static void output (TreeSet<String> dataSet, String filename)throws IOException
    {
        PrintWriter out = new PrintWriter(filename);
        for(var i:dataSet)
        {
            out.println(i);
        }
        out.close();
    }
    public static void main(String []args)throws IOException
    {
        String filename1="Week15/merge/datafile1.txt";
        String filename2="Week15/merge/datafile2.txt";
        String filename3="Week15/merge/datafile3.txt";
        TreeSet<String> dataSet=new TreeSet<String>();
        input(dataSet,filename1,filename2);
        output(dataSet,filename3);
    }
}