java - 将字母数字转换为 ascii 并递增

Question

我对如何将 3 个字母和 3 个数字转换为 ascii 并将它们递增 1 感到困惑...这是旧的 next-license-plate 问题。谁能给我一个正确方向的插入？

Answer 1

这个问题其实有实际应用。我写了一个帐号生成器，就像这样工作。我把它修改成你的格式。给你，

public class LicenseNumber {

    int numericSum;
    int letterSum;

    public LicenseNumber() {
        numericSum = letterSum = 0;
    }

    public LicenseNumber(String number) {
        if (!number.matches("^[A-Za-z]{3}[0-9]{3}$"))
            throw new IllegalArgumentException("Number doesn't match license format");
        numericSum = Integer.valueOf(number.substring(3));
        letterSum = value(number, 0) * 26 * 26 + value(number, 1) * 26 + 
           value(number, 2);
    }

    public void increment() {
        increment(1);
    }

    public void increment(int inc) {
        numericSum += inc;
        if (numericSum >= 1000) {
            letterSum += numericSum/1000;
            numericSum %= 1000;         
        }
    }

    public String toString() {
        char[] letters = new char[3];
        int n = letterSum;
        for (int i = 0; i < 3; i++) {
            letters[2-i] = (char)('A' + (n%26));
            n /= 26;
        }
        return new String(letters) + String.format("%03d", numericSum);
    }

    private int value(String s, int index) {
        return Character.toUpperCase(s.charAt(index)) - 'A';
    }

/**
     * Example
     */
    public static void main(String[] args) {

        LicenseNumber lic = new LicenseNumber("ABC999");
        for (int i=0; i < 100; i++) {
            lic.increment(500);
            System.out.println(lic);
        }
    }

}