第五周任务1-3

#include <iostream>
#include <cmath>
using namespace std;
class Triangle
{
public:

	float perimeter(void);
	float area(void);
	void showMessage();
	Triangle(float x=1,float y=2,float z=2);
private:
	float a,b,c;
};
void main()
{
	Triangle Tri1;
	Tri1.showMessage();


}
float Triangle::perimeter(void)
{
	return (a+b+c);
}
float Triangle::area(void)
{
	float s,m;
	s=(a+b+c)/2;
	m=sqrt(s*(s-a)*(s-b)*(s-c));
	return m;
}
void Triangle::showMessage()
{
	cout<<"三角形的三边为： "<<a<<'\t'<<b<<'\t'<<c<<endl;
	cout<<"该三角形的周长为："<<perimeter()<<'\t'<<"面积为："<<area()<<endl;
}
Triangle::Triangle(float x,float y,float z)
{
	a=x;
	b=y;
	c=z;
}