Java 程序打印出 0 而不是百分比

Question

我正在做一个项目，但程序的这一部分不起作用。它要求输入一个字符，然后读取给定的文本文件，并输出该字母在文本文件中出现的百分比。这是代码:

public static void inputLetterFrequency() {
    String letterInput = JOptionPane.showInputDialog("Please input a letter to find out the frequency");
    letterInput.toUpperCase();
    char c = letterInput.charAt(0);
    content = content.toUpperCase();

    for (int i = 0; i < content.length(); i++) {
        if (content.charAt(i) == c) {
            letterOccurence++;
        }
    }

    letterFrequency = (letterOccurence / numberCharacters) * 100.0;

    JOptionPane.showMessageDialog(null, "Frequency of letter " + c + " is " + letterFrequency + "%");
    String tryAgain = JOptionPane.showInputDialog("Please choose an option: \n1 to input another letter \n2 to exit ");
    int n = Integer.parseInt(tryAgain);
    if (n == 1) {
        CharacterAnalyzer.inputLetterFrequency();
    } else {
        System.exit(0);
    }

在文件开头声明如下

public static int numberCharacters;
public static String Filename = UserPrompt.content;
public static int letterOccurence;
public static double letterFrequency;
public static int digitOccurence;
public static double digitFrequency;

Answer 1

这是计算 letterFrequency 的代码:-

letterFrequency = (letterOccurence / numberCharacters) * 100.0;

只需将上面的代码改成:-

letterFrequency = letterOccurence * 100.0 / numberCharacters;

---

在第一个代码中:- (letterOccurence/numberCharacters) 将首先被计算，因为这是一个整数除法，它的结果将是0，如果 numerator 小于 denominator。

要使其成为浮点除法，只需在除法之前将分子乘以100.0。