public static Graph createGraph(string type)
{
Graph shape = null;
switch (type)
{
case "圆":
Console.WriteLine("请输入半径：");
string s = Console.ReadLine();
double R = Double.Parse(s);
shape = new circle {
r = R
};
break;
case "三角形":
Console.WriteLine("请输入三边（整形）：");
s = Console.ReadLine();
int a = int.Parse(s);
s = Console.ReadLine();
int b = int.Parse(s);
s = Console.ReadLine();
int c = int.Parse(s);
shape = new triangle {
a = a, b = b, c = c
};
break;
case "正方形":
Console.WriteLine("请输入边长：");
s = Console.ReadLine();
double L = double.Parse(s);
shape = new square {
L = L
};
break;
case "长方形":
Console.WriteLine("请输入两边长：");
s = Console.ReadLine();
L = double.Parse(s);
s = Console.ReadLine();
double K = double.Parse(s);
shape = new rectangle {
L = L, K = K
};
break;
}
return(shape);
}