第三次实验参考程序

参考代码

/**********************************************************/   
  //Function                                :   main,Triangle类
  //parm                                    :     
  //comment                                 :      
  //return                                  :   void  
  //Author                                  :      
  //date                                    :   2010.10.25  
/**********************************************************/
#include <iostream.h>
#include <stdlib.h>
#include <math.h>

class Triangle{
public:
	Triangle(double x,double y,double z)
	{
		a = x;
		b = y;
		c = z;
	}

	Triangle(double x,double y)
	{
		a = x;
		b = x;
		c = y;
	}

	Triangle(double x)
	{
		a = x;
		b = x;
		c = x;
	}

	Triangle()
	{
		a = 5;
		b = 5;
		c = 5;
	}

	double GetArea()
	{
		double k=(a + b + c) / 2;
		return sqrt( k * (k - a) * (k - b) * (k - c));
	}

	double GetPerimeter()
	{
		return a + b + c;
	}

	int TriangleType();

	void Show();
private:
	double a,b,c;
};

int Triangle::TriangleType()    //This function can be optimized!
{
	if(a <= 0 || b <= 0 || c <= 0 || a + b < c || a + c < b || b + c < a)
		return 0;    //wrong
	else
	{
		if(a == b && b == c)
			return 1;    //equilateral triangle
		else 
		{
			if(a == b || b == c)
			{
				if(a * a + b * b - c * c < 1e-3 ||
					a * a + c + c - b * b < 1e-3 || 
					b * b + c * c - a * a < 1e-3)
					return 2;    //isoceles triangle right-angled triangle
				else
					return 3;    //isoceles triangle
			}
			else
			{
				if(a * a + b * b == c * c || 
					a * a + c * c == b * b || 
					b * b + c * c == a * a)
					return 4;    //right-angled triangle
			}
		}
	}
	return 5;
}

void Triangle::Show()
{
	int flag;
	cout<<"The Triangle's sides are:"<<a<<","<<b<<","<<c<<endl;
	flag = TriangleType();
	switch(flag)
	{
		case 0: cout<<"The Triangle data is wrong!"<<endl; break;
		case 1: cout<<"The Triangle is equilateral triangle!"<<endl; break;
		case 2: cout<<"The Triangle is isoceles triangle right-angled triangle!"<<endl; break;
		case 3: cout<<"The Triangle is isoceles triangle!"<<endl; break;
		case 4: cout<<"The Triangle is right-angled triangle!"<<endl; break;
		case 5: cout<<"The Triangle is general triangle!"<<endl; break;
	}
	if(!TriangleType())
			exit(0);
	cout<<"The Triangle's Area is:"<<GetArea()<<endl;
	cout<<"The Triangle's Perimeter is:"<<GetPerimeter()<<endl;
}

void main()
{
	double a,b,c;
	cout<<"Please input the three sides of Triangle:"<<endl;
	cin>>a>>b>>c;
	Triangle T1(a,b,c);
	//Triangle T2(a,b);
	//Triangle T3(a);
	//Triangle T4;
	T1.Show();
	//T2.Show();
	//T3.Show();
	//T4.Show();
}