java - 如何修复 Java 中错误计算数字百分比的程序？

Question

我试图找出文档中每个字母的频率，因此该程序计算每个字母出现的次数，然后找到字母的总数。然后它应该找到频率，问题是它正确地计算了字母和总数，但百分比错误。如何计算百分比？

  //find number of occurrences for each letter
    String[] letter = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};      
    int[] count = new int[26];
    int totalCount = 0;

    for(int i = 0; i < subset.length(); i++)
    {
        char letters = subset.charAt(i);
        if(letters == 'a')
            count[0]++;
        else if(letters == 'b')
            count[1]++;
        else if(letters == 'c')
            count[2]++;
        else if(letters == 'd')
            count[3]++;
        else if(letters == 'e')
            count[4]++;
        else if(letters == 'f')
            count[5]++;
        else if(letters == 'g')
            count[6]++;
        else if(letters == 'h')
            count[7]++;
        else if(letters == 'i')
            count[8]++;
        else if(letters == 'j')
            count[9]++;
        else if(letters == 'k')
            count[10]++;
        else if(letters == 'l')
            count[11]++;
        else if(letters == 'm')
            count[12]++;
        else if(letters == 'n')
            count[13]++;
        else if(letters == 'o')
            count[14]++;
        else if(letters == 'p')
            count[15]++;
        else if(letters == 'q')
            count[16]++;
        else if(letters == 'r')
            count[17]++;
        else if(letters == 's')
            count[18]++;
        else if(letters == 't')
            count[19]++;
        else if(letters == 'u')
            count[20]++;
        else if(letters == 'v')
            count[21]++;
        else if(letters == 'w')
            count[22]++;
        else if(letters == 'x')
            count[23]++;
        else if(letters == 'y')
            count[24]++;
        else if(letters == 'z')
            count[25]++;
    }

    //find total characters in document                
    double[] frequency = new double[26];
    for(int i = 0; i < 26; i++)
    {
        totalCount += count[i];
        frequency[i] = ((double)count[i] / (totalCount + 1)) * 100;        //the problem
    }
    System.out.println(totalCount); 


    //for(int i = 0; i < 26; i++)
        //{
        //    frequency[i] = (double)(count[i] / totalCount * 100);
        //}


    //print 
    System.out.println(" Letter  Occurrences  Frequency");
    System.out.println("--------------------------------");
    for(int i = 0; i < 26; i++)
    {
        System.out.println("  " + letter[i] + "\t  " + count[i] + "\t       " + df.format(frequency[i]));
    }

Answer 1

获得总计数后需要计算频率:

for(int i = 0; i < 26; i++) { 
    totalCount += count[i]; 
} 
System.out.println(totalCount);  

System.out.println(" Letter Occurrences Frequency"); 

System.out.println("--------------------------------");     
for(int i = 0; i < 26; i++) { 
    frequency[i] = ((double)count[i] / (totalCount + 1)) * 100;
    System.out.println(" " + letter[i] + "\t " + count[i] + "\t " + df.format(frequency[i])); 
}

旁注

• totalCount 不需要 for 循环，因为它只是字符串的长度(即 totalCount =subset.length())

• 您不需要 25 个 if else 语句来查找字母计数.​​..只需执行以下操作: 计数[subset.charAt(i) - 61]++; 61 是字母“a”的 ASCII 值