circle.cpp

设计一个算法

#include<math.h>
#include<iostream.h>
#include<fstream.h>
#include<iomanip.h >
#define pi 3.1415926
class geometry {
public:
	geometry(double,double);
	geometry(double);
	~geometry(){}
	double getarea_s();
    double getarea_c();
	double getgirth_s();
    double getgirth_c();
	double getlong();
private:
	double m1,m2;
};
geometry::geometry(double r1,double r2)
{
     m1=r1;
	 m2=r2;
}
geometry::geometry(double r)
{
	m1=r;
	m2=0.0;
}
double geometry::getarea_s()
{
	return (m1*m2);
}
double geometry::getarea_c()
{
	return (m1*m1*pi);
}
double geometry::getgirth_c()
{
	return (2*m1*pi);
}
double geometry::getgirth_s()
{
	return (2*(m1+m2));
}
double geometry::getlong()
{
	return (sqrt(m1*m1+m2*m2));
}
void main()
{
	double a;
	ifstream get("input.txt");
    get>>a;
	geometry c1(a);
	geometry s(2*a,2*a);
	geometry c2(0.5*s.getlong());
	ofstream out("output.txt");
	out<<c1.getarea_c()<<' '<<c1.getgirth_c()
	   <<"\n"<<s.getarea_s()<<' '<<s.getgirth_s()<<' '
       <<s.getlong()<<"\n"<<c2.getarea_c()<<' '
	   <<c2.getgirth_c()<<endl;
}