public ResponseResult CalculateDistance(BaseStrategyViewModel viewModel)
        {
            ResponseResult result = new ResponseResult();

            switch (viewModel.Unit)
            {
            case "km":
            {
                result = CalculateDistanceInKM(viewModel);
                break;
            }

            case "mile":
            {
                result = CalculateDistanceInMile(viewModel);
                break;
            }
            }

            return(result);
        }
 private ResponseResult CalculateDistanceInMile(BaseStrategyViewModel viewModel)
 {
     return(_strategy.CalculateDistanceInMile(viewModel));
 }