小编wil*_*ilx的帖子

我们$return在代码中使用变量时观察到奇怪的效果$return = foo($something);.是$return可变莫名其妙特殊,因为的回归叫什么名字？

我知道可以使用bless函数和模块在Perl中创建类/对象.是否有任何CPAN模块可以使这更容易,最好是自动getter/setter生成？

我很擅长使用Node.js. 我一直在寻找一种解析和查询JSON对象的好方法.我将以下JSON对象作为文件加载.

[
{"Key":"Accept","Values":["Application/x-www-form-urlencoded","Application/Json","Application/Xml"]},
{"Key":"Accept-Charset","Values":["UTF-8", "ISO-8859-1"]},
{"Key":"Accept-Encoding","Values":["compress", "gzip"]},
{"Key":"Accept-Language","Values":[]},
{"Key":"Accept-Ranges","Values":[]},
{"Key":"Age","Values":[]},
{"Key":"Allow","Values":[]},
{"Key":"Authorization","Values":["Bearer"]},
{"Key":"Cache-Control","Values":[]},
{"Key":"Connection","Values":[]},
{"Key":"Content-Encoding","Values":[]},
{"Key":"Content-Language","Values":[]},
{"Key":"Content-Length","Values":[]},
{"Key":"Content-Location","Values":[]},
{"Key":"Content-MD5","Values":[]},
{"Key":"Content-Range","Values":[]},
{"Key":"Content-Type","Values":["Application/x-www-form-urlencoded","Application/Json","Application/Xml"]},
{"Key":"Date","Values":[]},
{"Key":"ETag","Values":[]},
{"Key":"Expect","Values":[]},
{"Key":"Expires","Values":[]},
{"Key":"From","Values":[]},
{"Key":"Host","Values":[]},
{"Key":"If-Match","Values":[]},
{"Key":"If-Modified-Since","Values":[]},
{"Key":"If-None-Match","Values":[]},
{"Key":"If-Range","Values":[]},
{"Key":"If-Unmodified-Since","Values":[]},
{"Key":"Last-Modified","Values":[]},
{"Key":"Max-Forwards","Values":[]},
{"Key":"Pragma","Values":[]},
{"Key":"Proxy-Authenticate","Values":[]},
{"Key":"Proxy-Authorization","Values":[]},
{"Key":"Range","Values":[]},
{"Key":"Referer","Values":[]},
{"Key":"TE","Values":[]},
{"Key":"Trailer","Values":[]},
{"Key":"Transfer-Encoding","Values":[]},
{"Key":"Upgrade","Values":[]},
{"Key":"User-Agent","Values":[]},
{"Key":"Via","Values":[]},
{"Key":"Warning","Values":[]}
]

我希望能够通过值找到Key并返回values数组.

因此,例如,如何找到键等于的值Content-Type.

在此先感谢您的帮助

我显示分区表的功能正常,但是我想格式化输出以允许小数点前面的任意数字,但是将后面的小数位数限制为2.这是我正在使用的代码.一旦我添加了该行,cout.setf(std::ios::fixed, std::ios::floatfield)我的数据似乎格式正确,但我在实际数字的前面附加了额外的数字.因此打印1.00程序而不是打印40981.00,它会对所有结果执行此操作.(前面的数字确实变为4102x.xx)x是所需的输出.

void print_div_values(mult_div_values ** table, float x, float y){

cout << endl << "Here is the division table: " << endl;

for (int i = 1; i <= y; i++)        
{
    cout << endl;

    for (int j = 1; j <= x; j++)    
    {
        cout << std::setw(5) << cout.setf(std::ios::fixed, std::ios::floatfield) << std::setprecision(2) << table[i][j].div;        
    }
    cout << endl;
}

我使用的是FreeBSD操作系统,我想写入磁盘上的文件,但是,这需要花费很多时间,因此,我建议使用内存映射文件.但是,我是否陷入困境,FreeBSD是否支持它？..请,有人可以指导我吗??我正在用C++编程.