Question

我试图使用正则表达式来确保为飞机输入的航向在o和360之间，但我无法使其工作。

std::regex headingCheck{"^([0-9]|1[0-9]2[0])$"};
    bool match = false;
    while (!match)
    {
        if (std::regex_match(heading, headingCheck))
        {
            heading_ = heading;
        }
        else
        {
            std::cout << "Invalid heading, can only be between 0 and 360 degrees" << std::endl;
        }
    }

＃

//Heading can only be between 0-360?
    if (heading >= 0 && heading <= 360)
    {
        heading_ = heading;
    }
    else
    {
        std::cout << "Incorrect heading, heading can only be between 0 and 360" << std::endl;
    }

我应该这样做吗？它是否准确/可靠？

Answer 1

如果您仍然需要正则表达式（尽管这不是最佳的），您可以使用以下表达式：

std::regex re{ "^[0-9]$|^[1-9][0-9]$|^[1-2][0-9][0-9]$|^3[0-5][0-9]$|^360$" };
std::string headings[5] = { "0","15","390","360","23883" };

for (int i = 0; i < 5; ++i)
    std::cout << "Heading " << headings[i] << " is " << (std::regex_match(headings[i], re) ? "valid" : "invalid") << std::endl;

第一部分匹配0-9，第二部分匹配10-99，第三部分匹配100-299，第四部分匹配300-359，最后匹配360.打印：

Heading 0 is valid
Heading 15 is valid
Heading 390 is invalid
Heading 360 is valid
Heading 23883 is invalid

正则表达式无效C ++

1 个答案: