10_86.cpp

C++程序设计技能百练随书配套光盘的源码

#include<iostream.h>
#include<math.h>
#include<iomanip.h>
class Triangle
{
	int x,y,z;
	double area;
public:
	Triangle();
	double getarea()
	{
		return area;
	}
	void dispArea()
	{
		cout<<setiosflags(ios::fixed)<<setprecision(2)<<area<<endl;
	}
	friend double operator+(Triangle t1,Triangle t2)
	{
		return t1.area+t2.area;
	}
	friend double operator+(double a,Triangle t)
	{
		return  a+t.area;
	}
	friend bool operator>(Triangle t1,Triangle t2)
	{
		return t1.area>t2.area ?true:false;
	}
};
Triangle::Triangle()
{
	int i,j,k;
	cout<<"请输入三角形的三边长：";
	cin>>i>>j>>k;
	if(i+j>k && i+k>j && j+k>i)
	{
		double s;
		x=i; y=j; z=k;
		s=(x+y+z)/2.0;
		area=sqrt(s*(s-x)*(s-y)*(s-z));
	}
	else
	{
		cout<<"错误！输入的三边长度不能构成三角形！"<<endl;
		area=x=y=z=0;
	}
}
void main()
{
	Triangle t1,t2,t3;
	cout<<"三角形1面积：";t1.dispArea();
	cout<<"三角形2面积：";t2.dispArea();
	cout<<"三角形3面积：";t3.dispArea();
	if(t1>t2)
		cout<<"三角形1面积比三角形2大："
		<<t1.getarea()-t2.getarea()<<endl;
	else
	    cout<<"三角形2面积比三角形1大："
		<<t2.getarea()-t1.getarea()<<endl;
	cout<<"总面积："<<t1+t2+t3<<endl;
}