用c++实现luhns算法

#include <iostream>
#include <string>

bool luhnAlgorithm(const std::string& number) {
    int sum = 0;
    bool alternate = false;

    for (int i = number.length() - 1; i >= 0; i--) {
        int digit = number[i] - '0';

        if (alternate) {
            digit *= 2;
            if (digit > 9) {
                digit = (digit % 10) + 1;
            }
        }

        sum += digit;
        alternate = !alternate;
    }

    return (sum % 10 == 0);
}

int main() {
    std::string number;
    std::cout << "请输入要验证的数字串：";
    std::cin >> number;

    if (luhnAlgorithm(number)) {
        std::cout << "该数字串是有效的。" << std::endl;
    } else {
        std::cout << "该数字串是无效的。" << std::endl;
    }

    return 0;
}