抽象方法:实现两个数的加、减、乘操作运算
1)、代码:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Calculate
{
public abstract class SimpleMath
{
public abstract void numeration(double x, double y);
}
class add : SimpleMath
{
public override void numeration(