【java】文件操作小測——統計英文文本出現頻率最高的字母

一、題目描述

 二、基本思路

通過FileReader讀取到文件，通過readLine讀取字符串，拆成字符進行判斷，這裏使用最笨的方法用大小為52的數組存儲各個字母出現的頻次，通過ascii碼聯係數字與字母，排序後輸出即可。

三、源碼及結果

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.text.DecimalFormat;

public class sumNovel {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        File f = new File("Harry Potter and the Sorcerer's Stone.txt");
        FileReader fr = null;
        BufferedReader br = null;
        try {
            DecimalFormat df = new DecimalFormat("0.00");
            fr = new FileReader(f);
            br = new BufferedReader(fr);
            String str = null;
            double[] sum = new double[52];
            double[] result = new double[52];
            int[] order = new int[52];
            for(int i=0;i<52;i++)
            {
                sum[i] = 0;
                order[i] = i;
            }
            double all = 0;
            while((str = br.readLine())!=null)
            {
                char[] array = str.toCharArray();
                for(int i=0;i<array.length;i++)
                {
                    int x = Integer.valueOf(array[i]);
                    if(x>=65&&x<=90)
                    {
                        int j=x-65;
                        sum[j]++;
                        all++;
                    }else if(x>=97&&x<=122)
                    {
                        int j=x-97+26;
                        sum[j]++;
                        all++;
                    }
                }
            }
            for(int i=0;i<52;i++)
            {
                result[i] = sum[i]/all;
            }
            
            for (int i = 0; i < 52; i++) {
                int maxIndex = i;
                for (int j = i; j < 52; j++) {
                    if (result[order[j]] > result[order[maxIndex]]) 
                        maxIndex = j; 
                }
                int temp = order[maxIndex];
                order[maxIndex] = order[i];
                order[i] = temp;
            }
            for(int i=0;i<52;i++)
            {
                if(order[i]>=0&&order[i]<=25)
                {
                    double j = order[i]+65;
                    char e = (char)j;
                    System.out.print(e+":");
                }else{
                    double j = order[i]+97-26;
                    char e = (char)j;
                    System.out.print(e+":");
                }
                double x = result[order[i]]*100;
                System.out.println(df.format(x)+"%");
            }
            
        } catch (Exception e) {
            // TODO: handle exception
        }
    }

}