C++实验一+简单计算问题体验

#include<iostream.h>
void main()
{
const double PI=3.1415926;
double radius;
double area;
double circumference;
cout<<"输入半径:";
cin>>radius;
area=PI*radius*radius;
circumference=2.0*PI*radius;
cout<<"输出圆的面积"<<radius<<"是"<<area<<"\n";
cout<<"和圆的周长"<<circumference<<"\n";
}