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| using System;
namespace Triangle_IO
{
public interface ITriangle
{
float area(float baseSide, float height);
float area(float a, float b, float c);
float area(float a, float b, double angleC);
float area(float r, double angleA, double angleB, double angleC);
}
public class Triangle : ITriangle
{
public float area(float baseSide, float height)
{
return baseSide * height / 2;
}
public float area(float a, float b, float c)
{
float p = (a + b + c) / 2;
return (float)Math.Sqrt(p * (p - a) * (p - b) * (p - c));
}
public float area(float a, float b, double angleC)
{
return a * b * (float)Math.Sin(angleC) / 2;
}
public float area(float r, double angleA, double angleB, double angleC)
{
return (float)(2 * Math.Pow(r, 2) * Math.Sin(angleA) * Math.Sin(angleB) * Math.Sin(angleC));
}
class Test
{
static void Main()
{
Console.WriteLine("请输入三角形的第一条边：");
float a = float.Parse(Console.ReadLine());
Console.WriteLine("请输入三角形的第二条边：");
float b = float.Parse(Console.ReadLine());
Console.WriteLine("请输入三角形的第三条边：");
float c = float.Parse(Console.ReadLine());
double angleA = Math.Acos((Math.Pow(b, 2) + Math.Pow(c, 2) - Math.Pow(a, 2)) / (2 * b * c));
double angleB = Math.Acos((Math.Pow(a, 2) + Math.Pow(c, 2) - Math.Pow(b, 2)) / (2 * a * c));
double angleC = Math.PI - angleA - angleB;
float height = a * (float)Math.Sin(angleC);
float baseSide = b;
float r = a / (2 * (float)Math.Sin(angleA));
Triangle triangle = new Triangle();
Console.WriteLine("三角形面积为：{0:f3}", triangle.area(baseSide, height));
Console.WriteLine("三角形面积为：{0:f3}", triangle.area(a, b, angleC));
Console.WriteLine("三角形面积为：{0:f3}", triangle.area(a, b, c));
Console.WriteLine("三角形面积为：{0:f3}", triangle.area(r, angleA, angleB, angleC));
}
}
}
}
|
