Question

程序需要计算并显示指定的charector在文本文件中出现的次数。

目前总数为零。我不是，如果我应该使用不同的循环，我也尝试使用'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

    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);

这有任何帮助吗？

Answer 2

您的代码中存在错误。下面的错误代码 -

   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);

Answer 3

这个答案假设你的文本文件中的每一行只包含一个字母，如你的问题所示。

您需要将if语句包装在循环中，因为当前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
         }
     }

您也可以替换：

count++;
total+= count;

只是

total++;

Answer 4

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

 }
}

计数字母发生

4 个答案: