C++ XML类
该类主要将xml中的标签分为两类，无内容标签统一称为父标签，有内容的就以键值对的方式直接输出。
后面可能会优化通过函数参数的方式管控层级关系，现在是通过类里自动记录层级深度来表示的。

#include <fstream>
#include <string>
#include <iostream>
#include <map>class XmlWriter {
private:std::ofstream m_file;public:XmlWriter(const std::string& filename) {m_file.open(filename.c_str());if (!m_file) {std::cout << "" << std::endl;}m_file << "<?xml version=\"1.0\" encoding = \"UTF-8\"?> \n";depth = 0;}~XmlWriter() {if (m_file) {m_file.close();}}void addParentElement(const std::string& parentLable = "") {if (!parentLable.empty()) {if (depth) {for (int i = 0; i < depth; i++)m_file << "  ";}m_file << "<" << parentLable << ">\n";depth++;m_LableMap[depth]= parentLable;}}void addLableKey(const std::string& key, const std::string& value = "") {if (!key.empty() && !value.empty()) {if (depth){for (int i = 0; i < depth; i++)m_file << "  ";}m_file << "<" << key << ">" << value << "</" << key << ">\n";}}void closeParentElement() {if (depth){for (int i = 0; i < depth - 1 ; i++)m_file << "  ";}m_file << "</" << m_LableMap[depth] << ">\n";m_LableMap.erase(depth);depth--;}private:int depth;std::map<int, std::string> m_LableMap;};int main(int argc, char * argv[])
{XmlWriter writer("mateDate.xml");writer.addParentElement("Person");writer.addLableKey("Age", "27"); writer.addLableKey("name", "hzh");writer.addParentElement("friend");writer.addLableKey("name", "zjm");writer.addLableKey("Age", "22");writer.closeParentElement();writer.addLableKey("pay", "30w");writer.closeParentElement();return 0;
}