c++实现两个版本号比较

https://blog.csdn.net/lyd_253261362/article/details/50916293

//retval: 0:相等；1： 大于此版本，-1：小于当前版本 3：其他情况；
int CTools::ComparerVersion(char * version_get ,char * version)
{
	string strversion_get = version_get;
	string strversion = version;
	if (strversion_get.empty() || strversion.empty())
	{
		return 3;
	}
 
	size_t pos = 0;
	int number = 0;
	string pattern(".");
	int icpt = pattern.size();
	std::vector<string> result;
	int iposbf = 0;
	while(pos != string::npos)
	{
		pos = strversion_get.find(pattern, pos);
		if(pos != string::npos)
		{
			int istart = iposbf;
			if (0 ==istart)
			{
			}
			else
			{
				istart = istart + icpt;
			}

			std::string s = strversion_get.substr(istart,pos - istart);
			result.push_back(s);
			++number;
			iposbf = pos;
			pos += (pattern.size() + 1);

		}
		else
		{   
			iposbf += (pattern.size()); 
			std::string s = strversion_get.substr(iposbf,strversion_get.size());
			result.push_back(s);
		}
	}
	////////////////////////////////////////////////////
	if (number != 3)
	{
		return 3;
	}

	//////////////////////////////////////////////////////
	size_t pos_v = 0;
	int number_v = 0;
	string pattern_v(".");
	int icpt_v = pattern_v.size();
	std::vector<string> result_v;
	int iposbf_v = 0;
	while(pos_v != string::npos)
	{
		pos_v = strversion.find(pattern_v, pos_v);
		if(pos_v != string::npos)
		{
			int istart_v = iposbf_v;
			if (0 ==istart_v)
			{
			}
			else
			{
				istart_v = istart_v + icpt_v;
			}

			std::string s_v = strversion.substr(istart_v,pos_v - istart_v);
			result_v.push_back(s_v);
			++number_v;
			iposbf_v = pos_v;
			pos_v += (pattern_v.size() + 1);
		}
		else
		{
			iposbf_v += (pattern_v.size());
			std::string s_v = strversion.substr(iposbf_v,strversion.size());
			result_v.push_back(s_v);
		}
	}
	if (number_v != 3)
	{
		return 3;
	}

	//////////////////////////////////////////////////////
	ostringstream oversion;
	for(int i=0; i < result.size(); i++)
	{
		oversion<<result[i].c_str();
	}

	ostringstream oversionv;
	for(int j=0; j < result_v.size(); j++)
	{
		oversionv<<result_v[j].c_str();
 	}

	for(int m=0; m < result.size(); m++)
	{
		oversion<<result[m].c_str(); 
		int istrcmp = 0;
		istrcmp = result[m].compare(result_v[m]);
		if ( istrcmp == 0)
		{
			if (m == result.size() -1)
			{
				return 0;
			}
		}
		else if( istrcmp == 1)
		{
			return 1;
		}
		else if (istrcmp < 0)
		{
			return -1;
		}
	}
	return 0;
}

　　int iRetVersion = CTools::ComparerVersion("6.2.1512.491","6.6.1512.409");