Question

求 如何C#语言 判断数学表达式是否正确的代码 最多四个运算符

Answer 1

class Basic
{
private static double numA; //字段
private static double numB; //字段 public static double NumA //数字一
{
get { return numA; }
set { numA = value; }
}
public static double NumB //数字二
{
get { return numB; }
set { numB = value; }
}
public virtual double GetResult() //虚方法
{
double result=0;
return result;
}
} class AddCaclc : Basic //继承Basic
{
public override double GetResult() // 改写GetResult 实现 +
{
double result = 0;
result = NumA + NumB;
return result;
}
} class SubCaclc : Basic //继承Basic
{
public override double GetResult() // 改写GetResult 实现 -
{
double result = 0;
result = NumA - NumB;
return result;
}
} class MulCaclc : Basic //继承Basic
{
public override double GetResult() // 改写GetResult 实现 *
{
double result = 0;
result = NumA * NumB;
return result;
}
} class DivCaclc : Basic //继承Basic
{
public override double GetResult() // 改写GetResult 实现 /
{
double result = 0;
if (NumB == 0) //判断除数
throw new Exception("除数不能为零！");
result = NumA / NumB;
return result;
}
} class Judge
{
public static Basic CreateJudge(string sign)
{
Basic basic = null;
switch (sign)
{
case "+": basic = new AddCaclc(); break;
case "-": basic = new SubCaclc(); break;
case "*": basic = new MulCaclc(); break;
case "/": basic = new DivCaclc(); break;
}
return basic;
}
}