C # 스위치와 함께 열거 형을 사용하는 방법

C # 스위치와 함께 열거 형을 사용하는 방법

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열거 형과 함께 스위치를 사용하는 방법을 알 수 없습니다. 내가 뭘 잘못하고 있고 어떻게 고칠 수 있는지 말해 주시겠습니까? 기본 계산기를 만들려면 열거 형을 사용해야합니다.

public enum Operator
{
    PLUS, MINUS, MULTIPLY, DIVIDE
}

public double Calculate(int left, int right, Operator op)
{

    int i = (int) op;

    switch(i)
    {
        case 0:
        {
            return left + right;
        }

        case 1:
        {
            return left - right;
        }

        case 2:
        { 
            return left * right;
        }

        case 3:
        {
            return left / right;
        }

        default:
        {
            return 0.0;
        }
    }
}

최종 결과는 다음과 같아야합니다.

Console.WriteLine("The sum of 5 and 5 is " + Calculate(5, 5, PLUS))
Output: The sum of 5 and 5 is 10

내가 어떻게 엉망이되는지 말해 줄래?

---

변환 할 필요가 없습니다.

switch(op)
{
     case Operator.PLUS:
     {
        // your code 
        // for plus operator
        break;
     }
     case Operator.MULTIPLY:
     {
        // your code 
        // for MULTIPLY operator
        break;
     }
     default: break;
}

그건 그렇고, 대괄호를 사용하십시오

---

정답은 이미 주어졌지만 여기에 스위치보다 더 좋은 방법이 있습니다.

private Dictionary<Operator, Func<int, int, double>> operators =
    new Dictionary<Operator, Func<int, int, double>>
    {
        { Operator.PLUS, ( a, b ) => a + b },
        { Operator.MINUS, ( a, b ) => a - b },
        { Operator.MULTIPLY, ( a, b ) => a * b },
        { Operator.DIVIDE ( a, b ) => (double)a / b },
    };

public double Calculate( int left, int right, Operator op )
{
    return operators.ContainsKey( op ) ? operators[ op ]( left, right ) : 0.0;
}

---

단순히 int로 캐스트하지 마십시오.

 switch(operator)
    {
       case Operator.Plus:
       //todo

---

정수로 캐스트해서는 안됩니다. 그리고 나눗셈의 경우 정수 나눗셈을 수행하지 않을 경우 먼저 왼쪽에서 두 배로 캐스팅해야합니다.

public enum Operator
{
    PLUS, MINUS, MULTIPLY, DIVIDE
}

public double Calculate(int left, int right, Operator op)
{
    double sum = 0.0;

    switch(op)
    {
       case Operator.PLUS:
       sum = left + right;
       return sum;

       case Operator.MINUS:
       sum = left - right;
       return sum;

       case Operator.MULTIPLY:
       sum = left * right;
       return sum;

       case Operator.DIVIDE:
       sum = (double)left / right;
       return sum;

       default:
       return sum;
   }

   return sum;
}

---

 public enum Operator
    {
        PLUS, MINUS, MULTIPLY, DIVIDE
    }

    public class Calc
    {
        public void Calculate(int left, int right, Operator op)
        {

            switch (op)
            {
                case Operator.DIVIDE:
                    //Divide
                    break;
                case Operator.MINUS:
                    //Minus
                    break;
                case Operator.MULTIPLY:
                    //...
                    break;
                case Operator.PLUS:
                    //;;
                    break;
                default:
                    throw new InvalidOperationException("Couldn't process operation: " + op);
            }
        }
    }

---

각 경우에 return 문을 사용하지 않으려면 다음을 시도하십시오.

Calculate(int left, int right, Operator op)
{
   int result = 0;
   switch(op)
   {
        case Operator.PLUS:
        {
            result = left + right;;  
        }
        break;
        ....
   }

   return result;
}

---

다른 모든 답변은 정확하지만 메서드를 올바르게 호출해야합니다.

Calculate(5, 5, Operator.PLUS))

And since you use int for left and right, the result will be int as well (3/2 will result in 1). you could cast to double before calculating the result or modify your parameters to accept double

---

Two things. First, you need to qualify the enum reference in your test - rather than "PLUS", it should be "Operator.PLUS". Second, this code would be a lot more readable if you used the enum member names rather than their integral values in the switch statement. I've updated your code:

public enum Operator
{
    PLUS, MINUS, MULTIPLY, DIVIDE
}

public static double Calculate(int left, int right, Operator op)
{
    switch (op)
    {
        default:
        case Operator.PLUS:
            return left + right;

        case Operator.MINUS:
            return left - right;

        case Operator.MULTIPLY:
            return left * right;

        case Operator.DIVIDE:
            return left / right;
    }
}

Call this with:

Console.WriteLine("The sum of 5 and 5 is " + Calculate(5, 5, Operator.PLUS));

---

Your code is fine. In case you're not sure how to use Calculate function, try

Calculate(5,5,(Operator)0); //this will add 5,5
Calculate(5,5,Operator.PLUS);// alternate

Default enum values start from 0 and increase by one for following elements, until you assign different values. Also you can do :

public enum Operator{PLUS=21,MINUS=345,MULTIPLY=98,DIVIDE=100};

---

No need to convert. You can apply conditions on Enums inside a switch. Like so,

public enum Operator
{ 
    PLUS,
    MINUS,
    MULTIPLY,
    DIVIDE
}

public double Calculate(int left, int right, Operator op)
{
    switch (op)
    {
        case Operator.PLUS: return left + right; 
        case Operator.MINUS: return left - right; 
        case Operator.MULTIPLY: return left * right;
        case Operator.DIVIDE: return left / right;
        default: return 0.0; 
    }
}

Then, call it like this:

Console.WriteLine("The sum of 5 and 5 is " + Calculate(5, 5, Operator.PLUS));

참고URL : https://stackoverflow.com/questions/15136134/c-sharp-how-to-use-enum-with-switch