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求10000内的水仙花数

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  • java
 
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package equals;

import java.io.File;
import java.io.FileWriter;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.BufferedReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * 
 * @author me
 * 将10000数写入一txt文件,从中找出所有的水仙花数,
 * 将结果写入另一文件
 */
public class FileNumHandle {
	
	private static final int MAX = 10000;
	private static final String inPath = "G:/test/java/file/1.txt";
	private static final String outPath = "G:/test/java/file/2.txt";
	
	public static void createFile(String path){

		try{
			String dir = path.substring(0,path.lastIndexOf("/"));
			File dirPath = new File(dir);
			if(!dirPath.exists()){
				dirPath.mkdir();
			}
		}catch(Exception e){
			System.out.println("目录不可创建,请检查权限及盘符");
		}
		
		try{
			File file = new File(path);
			if(!file.exists()){
				file.createNewFile();
			}
		}catch(Exception e){
			System.out.println("文件不可创建,请检查权限及盘符");
		}
	}
	
	public static void WriteNumToFile(int max,String path){
		createFile(path);
		
		try{
			FileWriter fw = new FileWriter(path);
			BufferedWriter bw = new BufferedWriter(fw);
			for(int i = 0; i < max; i++){
				bw.write(String.valueOf(i));
				bw.newLine();
			}
			bw.flush();
			bw.close();
			fw.close();
		}catch(IOException e){
			e.printStackTrace();
		}
	}
	public static void WriteNumToFile(List a,String path){
		createFile(path);
		
		try{
			FileWriter fw = new FileWriter(path);
			BufferedWriter bw = new BufferedWriter(fw);
			for(int i = 0; i < a.size(); i++){
				bw.write(String.valueOf(a.get(i)));
				bw.newLine();
			}
			bw.flush();
			bw.close();
			fw.close();
		}catch(IOException e){
			e.printStackTrace();
		}
	}
	
	public static List narcissusNum(String inPath){
		List list = new ArrayList();
		try{
			String line="";
			int tmpNum = 0;
			int i,j,k,m;//千位、百位、十位、个位
			FileReader fr = new FileReader(inPath);
			BufferedReader br = new BufferedReader(fr);
			while(br.ready()){
				line = br.readLine();
				tmpNum = Integer.parseInt(line);
				i = tmpNum / 1000;
				j = tmpNum / 100 % 10;
				k = tmpNum % 100 / 10;
				m = tmpNum % 10;
				if(Math.pow(i, 3) + Math.pow(j, 3) + Math.pow(k, 3) + Math.pow(m, 3) == tmpNum){
					list.add(tmpNum);
				}
			}
			
		}catch(IOException e){
			e.printStackTrace();
		}
		return list;
	}
	public static void main(String[] args){
		WriteNumToFile(MAX,inPath);
		WriteNumToFile(narcissusNum(inPath),outPath);
	}
}


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