c++ - 如何获得C++或Qt中所有货币符号和货币缩写的数组？

Question

我需要在程序中以数组的形式获取所有可能的货币符号和货币缩写。如何使用C++或Qt来实现？

Answer 1

解析现有最新货币列表

我找到了货币代码JSON列表https://gist.github.com/Fluidbyte/2973986。
此列表会定期更新。

如何解析列表。从链接下载原始JSON文本。将其保存到UTF-8编码的文本文件中。解析后写在下面。

#include <QtWidgets/QApplication>    
#include <QVariantMap>
#include <QStringList>
#include <QJsonDocument>
#include <QJsonObject>
#include <QFile>
#include <QDebug>
#include <QPlainTextEdit>

using CurrencyMap = QMap<QString, QVariantMap>; // Use three-letter code as a key
using CurrencyMapIterator = QMapIterator<QString, QVariantMap>;

CurrencyMap parseCurrencyDataFromJson(QByteArray utf8Json)
{
    CurrencyMap ret;

    QJsonParseError parseError;
    QJsonDocument document = QJsonDocument::fromJson(utf8Json, &parseError);

    if (parseError.error != QJsonParseError::NoError)
    {
        qWarning() << parseError.errorString();
    }

    if (!document.isNull())
    {
        QJsonObject jobject = document.object();

        // Iterate over all the currencies
        for (QJsonValue val : jobject)
        {
            // Object of a given currency
            QJsonObject obj = val.toObject();

            // Three-letter code of the currency
            QString name = obj.value("code").toString();

            // All the data available for the given currency
            QVariantMap fields = obj.toVariantMap();

            ret.insert(name, fields);
        }
    }

    return ret;
}

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QPlainTextEdit plainTextEdit;
    plainTextEdit.show();

    // File saved from the GitHub repo
    QFile file("curr.json");
    if (file.open(QIODevice::ReadOnly))
    {
        QByteArray jsonData = file.readAll();

        CurrencyMap currencyMap = parseCurrencyDataFromJson(jsonData);

        // Output all the available currency symbols to the plainTextEdit
        CurrencyMapIterator currency(currencyMap);

        while (currency.hasNext())
        {
            currency.next();

            QString code = currency.key();
            QVariantMap fileds = currency.value();

            QStringList currencyInfo
            {
                code,
                fileds.value("symbol").toString(),
                fileds.value("symbol_native").toString()
            };

            plainTextEdit.appendPlainText(currencyInfo.join('\t'));
        }

        QString total = QString("\nTotal Available Currencies Count = %1")
            .arg(currencyMap.count());

        plainTextEdit.appendPlainText(total);
    }

    return a.exec();
}

QChar受限解决方案
QChar和基于Unicode的解决方案。但请注意， QChar本身仅支持最大0xFFFF的代码。因此，只能以这种方式检索有限数量的符号。

// In Qt, Unicode characters are 16-bit entities.
// QChar itself supports only codes with 0xFFFF maximum
QList<QChar> getAllUnicodeSymbolsForCategory(QChar::Category cat)
{
    QList<QChar> ret;

    // QChar actually stores 16-bit values
    const static quint16 QCharMaximum = 0xFFFF;

    for (quint16 val = 0; val < QCharMaximum; val++)
    {
        QChar ch(val);

        if (ch.category() == cat)
        {
            ret.append(ch);
        }
    }

    return ret; 
}

用法

QList<QChar> currencies = getAllUnicodeSymbolsForCategory(QChar::Symbol_Currency);