c++ 常用函数集锦

目录

 c++ 常用函数集锦

 1、string和wstring之间转换

 2、经纬度转 xyz 值 互转

 3 、获取 根目录下的文件地址

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 1、string和wstring之间转换

std::string convertWStringToString(std::wstring wstr)
{
	std::string str;
	if (!wstr.empty())
	{
		std::wstring_convert<std::codecvt_utf8<wchar_t>> converter;
		str = converter.to_bytes(wstr);
	}
	return str;
}

std::wstring convertStringToWString(std::string wstr)
{
	std::wstring str;
	if (!wstr.empty())
	{
		std::wstring_convert<std::codecvt_utf8<wchar_t>> converter;
		str = converter.from_bytes(wstr);
	}
	return str;
}

  2、经纬度转 xyz 值 互转

//经纬度 转 xyz
XYZ LBtoXYZ(double lontitude, double latitude, double height)
{
	double f = 1 / 298.25722293287;  //地球扁率
	double Re = 6378137.0;         //长半轴，单位：m
	double Rp = 6356752.3142;      //短半轴，单位：m
	double PI = 3.14159265;
	double R = 0;  //当量半径
	double Rdenominator = 0;
	Rdenominator = (1 - f)*(1 - f)*sin(latitude)*sin(latitude) + cos(latitude)*cos(latitude);
	//if(Rdenominator<=0)
	//	return ;

	R = Re / (sqrt(Rdenominator));  //

	XYZ res = { 0 };
	res.X = (R + height)*cos(latitude)*cos(lontitude);
	res.Y = (R + height)*cos(latitude)*sin(lontitude);
	res.Z = (R*(1 - f)*(1 - f) + height)*sin(latitude);
	return res;
}

// xyz 转 经纬度
BLH XYZtoLB(double X, double Y, double Z)
{
	double a, f, e2, B = 0.0, N = 0.0, H = 0.0, R0, R1, deltaH, deltaB;
	a = 6378137.0, f = (1.0 / 298.257223563), e2 = f*(2 - f);
	BLH res = { 0 };
	R0 = sqrt(pow(X, 2) + pow(Y, 2));
	R1 = sqrt(pow(X, 2) + pow(Y, 2) + pow(Z, 2));
	//经度直接求解
	res.L = atan2(Y, X);
	//迭代求大地维度和大地高
	N = a;
	H = R1 - a;
	B = atan2(Z * (N + H), R0 * (N * (1 - e2) + H));
	do
	{
		deltaH = N;//判断收敛所用
		deltaB = B;
		N = a / sqrt(1 - e2 * pow(sin(B), 2));
		H = R0 / cos(B) - N;
		B = atan2(Z * (N + H), R0 * (N * (1 - e2) + H));
	} while (fabs(deltaH - H) > 1.0e-3 && fabs(deltaB - B) > 1.0e-9);
	res.B = B;
	res.H = H;
	return res;
}

3 、获取 根目录下的文件地址

QString xxxxx::getConfigPath(QString fileName)
{
	QString appDirPath = QCoreApplication::applicationDirPath();
	return appDirPath + "/config/" + fileName;
}