Calculator

public class Calculator : ICalculator    {        public Calculator()        {            Logger = LogManager.GetCurrentClassLogger();        }        public ILogger Logger { get; set; }        public CalculationResult Add(string n1, string n2)        {            Logger?.Info($"received request to Add {n1} to {n2}");                       return Calculate(n1, n2, _add);        }        public CalculationResult Subtract(string n1, string n2)        {            Logger?.Info($"received request to Subtract {n2} from {n1}");                        return Calculate(n1, n2, _subtract);        }        public CalculationResult Multiply(string n1, string n2)        {            Logger?.Info($"received request to Multiply {n1} by {n2}");                        return Calculate(n1, n2, _multiply);        }        public CalculationResult Divide(string n1, string n2)        {            Logger?.Info($"received request to Divide {n1} by {n2}");                       return Calculate(n1, n2, _divide);        }        private static CalculationResult Calculate(string n1, string n2, Func
     
       calculate)        {            var value1 = n1.ToDouble();            if (!value1.HasValue)            {                return GetCouldNotConvertToDoubleResult(n1);            }            var value2 = n2.ToDouble();            if (!value2.HasValue)            {                return GetCouldNotConvertToDoubleResult(n2);            }            double result = calculate(value1.Value, value2.Value);            return new CalculationResult            {                Answer = result            };        }        private static readonly Func
      
        _add = (value1, value2) => value1 + value2;        private static readonly Func
       
         _subtract = (value1, value2) => value1 - value2;        private static readonly Func
        
          _multiply = (value1, value2) => value1 * value2;        private static readonly Func
         
           _divide = (value1, value2) => value2 == 0 ? double.NaN : value1 / value2;                private static CalculationResult GetCouldNotConvertToDoubleResult(string input)        {            return new CalculationResult            {                Message = $"Could not convert '{input}' to a double"            };        }    }
         
        
       
      
     

 

 

https://github.com/NotMyself/CalculatorService.git

http://www.cnblogs.com/jys509/p/4614975.html