初学C#语法,使用书上的例子模拟练习,编译的时候提示了一个错误,没想明白,请教各位错在哪里?using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;namespace test
{
class Calcdata
{
public delegate int delcalcdata(int x,int y);
public int Add(int x, int y)
{
return x + y;
}
public int Sub(int x, int y)
{
return x - y;
}
public int Mul(int x, int y)
{
return x * y;
}
public int Div(int x, int y)
{
return x / y;
}
public int ComputerData(string flag, int x, int y)
{
int result; //计算结果
flag = flag.ToLower();
delcalcdata obj;
switch (flag)
{
case "a":
obj = new delcalcdata(Add);
break;
case "b":
obj = new delcalcdata(Sub);
break;
case "c":
obj = new delcalcdata(Mul);
break;
case "d":
obj = new delcalcdata(Div);
break;
}
result = obj(x, y);
return result;
}
}
}
using System.Collections.Generic;
using System.Linq;
using System.Text;namespace test
{
class Calcdata
{
public delegate int delcalcdata(int x,int y);
public int Add(int x, int y)
{
return x + y;
}
public int Sub(int x, int y)
{
return x - y;
}
public int Mul(int x, int y)
{
return x * y;
}
public int Div(int x, int y)
{
return x / y;
}
public int ComputerData(string flag, int x, int y)
{
int result; //计算结果
flag = flag.ToLower();
delcalcdata obj;
switch (flag)
{
case "a":
obj = new delcalcdata(Add);
break;
case "b":
obj = new delcalcdata(Sub);
break;
case "c":
obj = new delcalcdata(Mul);
break;
case "d":
obj = new delcalcdata(Div);
break;
}
result = obj(x, y);
return result;
}
}
}
{
...
default:
obj = new delcalcdata(Add);
break;
}
int result; //计算结果
flag = flag.ToLower();
delcalcdata obj = null;
switch (flag)
{.. }