计数字母出现

Question

程序需要统计并显示指定字符在文本文件中出现的次数。

目前总数为零。如果我应该使用不同的循环，我不是，我也尝试过使用“for”循环。

// Hold user input and sum
String fileName;    // Holds the name of the file
String letter;      // Letter to search for in the file
int total = 0;      // Holds the total number of characters in the file


// Get the name of the file and character from the user
fileName = JOptionPane.showInputDialog("Please enter the name of a file:");
letter = JOptionPane.showInputDialog("Please enter a letter contained in the string");


// Open the file for reading
File file = new File(fileName);         
Scanner inputFile = new Scanner(file);  // Declare new scanner object for file reading


// Set accumulator to zero
int count = 0;

if (inputFile.nextLine().equalsIgnoreCase(letter)) {                                

    count++;          // add letter occurrence

    total += count;   // add the letter occurrence to the total
}

Answer 1

此答案假设您的文本文件中的每一行仅包含一个字母，正如您的问题所暗示的那样。

您需要将 if 语句包装在一个循环中，因为目前您只检查文件的第一行：

     while(inputFile.hasNext()) {
         if (inputFile.nextLine().equalsIgnoreCase(letter))    {                                

             count++;          // add letter occurrence

             total += count;   // add the letter occurrence to the total
         }
     }

你也可以替换：

count++;
total+= count;

只有

total++;

Answer 2

    BufferedReader reader = new BufferedReader(new FileReader("somefile.txt"));
    int ch;
    char charToSearch='a';
    int counter=0;
    while((ch=reader.read()) != -1) {
        if(charToSearch == (char)ch) {
            counter++;
        }
    };
    reader.close();

    System.out.println(counter);

这有什么帮助吗？

Answer 3

String line=""
while(inputFile.hasNext()) {
  line = inputFile.nextLine();
  for(int i=0; i<line.length(); i++ ){
     if (line.charAt(i)== letter)                                    
         count++;          

 }
}

Answer 4

您的代码中存在错误。下面是正确的代码-

   String fileName;    // Holds the name of the file
    String letter;      // Letter to search for in the file

    // Get the name of the file and character from the user
    fileName = "C:\\bin\\GWT.txt";
    letter = "X";


    // Open the file for reading
    File file = new File(fileName);         
    Scanner inputFile = new Scanner(file);  // Declare new scanner object for file reading


    // Set accumulator to zero
    int count = 0;
    while(inputFile.hasNext()) {
      if (inputFile.nextLine().toLowerCase().contains(letter.toLowercase())) { 
           count++;          // add letter occurrence
       }
    }
    System.out.println(count);