1、分别编写求圆面积和周长的函数，另编写一个主函数调用它们，要求主函数能输入多个园半径，且显示相应的圆面积和周长。
能够详细的说明下代码和 具体的步骤都是什么意思  谢谢了

#define 3.14159265 P
class Circle
{
    double m_r;
    public:
        double GetSpace() const
        {
            return P*m_r*m_r;
        }
        double GetLength
        {
            return 2*P*m_r;   
        }
}

int main
{
    cout << "输入圆的个数：" << endl;
    int n;
    cin >> n;
    double* p = new double[n];
    for(int i = 0; i < n; i++)
    {
        cout << "输入第" << i+1 << "个圆的半径" << endl;
        int t;
        cout << p[i].GetSpace();
        cout << p[i].GetLength();
    }
    delete p;
}

#define 3.14159265 P
class Circle
{
    double m_r;
    public:
        double GetSpace() const
        {
            return P*m_r*m_r;
        }
        double GetLength() const
        {
            return 2*P*m_r;   
        }
}

int main
{
    cout << "输入圆的个数：" << endl;
    int n;
    cin >> n;
    double* p = new double[n];
    for(int i = 0; i < n; i++)
    {
        cout << "输入第" << i+1 << "个圆的半径" << endl;
        cout << p[i].GetSpace();
        cout << p[i].GetLength();
    }
    delete p;
}

#define   P 3.1415
class Circle
{
public:
    double m_r;
    public:
        Circle(double r = 0) : m_r(r){}
        double GetSpace() const
        {
            return P*m_r*m_r;
        }
        double GetLength() const
        {
            return 2*P*m_r;   
        }
};

int main()
{
    cout << "输入圆的个数：" << endl;
    int n;
    cin >> n;
    Circle* p = new Circle[n];
    for(int i = 0; i < n; i++)
    {
        cout << "输入第" << i+1 << "个圆的半径" << endl;
        cin >> p[i].m_r;
        cout << p[i].GetSpace() << endl;
        cout << p[i].GetLength() << endl;
    }
    delete p;
    return 0;
}

1、分别编写求圆面积和周长的函数，另编写一个主函数调用它们，要求主函数能输入多个园半径，且显示相应的圆面积和周长。
能够详细的说明下代码和 具体的步骤都是什么意思  谢谢了
#include<iostream.h>
#define pi 3.1415926
double mianji(int r)
{
double s;
s=pi*r*r;
return(s)
}
double zhouchang(int r)
{
double l;
l=2*pi*r
return(l)
}
void main()
{
int n,i,j,a[100];
double b[100],c[100];
cout<<"输入圆的个数"<<endl;
cin>>n;
cout<<"输入个园的半径"<<endl;
for(i=0;i<n;i++)
cin>>a[i];
for(j=0;j<n;j++)
{
b[j]=mianji(b[j]);
c[j]=zhouchang(c[j]);
}
for(i=0;i<n;i++)
cout<<b[i];
cout<<endl;
for(i=0;i<n;i++)
cout<<c[i];
cout<<endl;
}

看来我学的还是太嫩了  看不懂啊