QString fileName(tr("output.xml"));
QFile file(fileName);
if (!file.open(QFile::WriteOnly | QFile::Text))
{
	std::cerr << "Error: Cannot open file" << std::endl;
}

QString strA(tr("A")),strB(tr("B")),strC(tr("C")),strD(tr("D"));

QXmlStreamWriter xmlWriter(&file);
xmlWriter.setAutoFormatting(true);
xmlWriter.writeStartDocument();
	xmlWriter.writeStartElement("result");
		xmlWriter.writeStartElement("A");
			xmlWriter.writeCharacters(strA);
		xmlWriter.writeEndElement();
		xmlWriter.writeStartElement("B");
			xmlWriter.writeCharacters(strB);
		xmlWriter.writeEndElement();
		xmlWriter.writeStartElement("C");
			xmlWriter.writeCharacters(strC);
		xmlWriter.writeEndElement();
		xmlWriter.writeStartElement("D");
			xmlWriter.writeCharacters(strD);
		xmlWriter.writeEndElement();
	xmlWriter.writeEndElement();
xmlWriter.writeEndDocument();
file.close();