public Shape RandomGetShape(int num)
{
switch (num % 3)
{
case 0:
Random ra1 = new Random();
double a1 = ra1.Next(-10, 11);
double b1 = ra1.Next(-10, 11);
Rectangle rec = new Rectangle(a1, b1);
if (rec.IsLegal())
{
Console.WriteLine("成功创建长方形！边长分别为" + rec.a + "与" + rec.b);
return(rec);
}
else
{
return(null);
}
case 1:
Random ra2 = new Random();
double a2 = ra2.Next(-10, 11);
Square squ = new Square(a2);
if (squ.IsLegal())
{
Console.WriteLine("成功创建正方形！边长为" + squ.a);
return(squ);
}
else
{
return(null);
}
case 2:
Random ra3 = new Random();
double a3 = ra3.Next(-10, 13);
double b3 = ra3.Next(-10, 13);
double c3 = ra3.Next(-10, 13);
Triangle tri = new Triangle(a3, b3, c3);
if (tri.IsLegal())
{
Console.WriteLine("成功创建三角形！边长分别为" + tri.a + "，" + tri.b + "，" + tri.c);
return(tri);
}
else
{
return(null);
}
default:
return(null);
}
}