帮我优化一下！

#include <iostream>
using namespace std;
int temp;
class CFT
{
private:
    double length;
    double width;
    double height;
    double S;
   
public:

    void set_value();
    void show_value();
   
};


void CFT::set_value()
{
    cout<<"please enter numbers for"<<" "<<temp<<":"<<endl;
    cout<<"length:";
    cin>>length;
    cout<<endl;
    cout<<"width:";
    cin>>width;
    cout<<endl;
    cout<<"height:";
    cin>>height;
    cout<<endl;
}
void CFT::show_value()
{
    S=length*width*height;
        cout<<"第"<<temp<<"个长方体的面积为："<<S<<endl;
}

int main()
{
    CFT a;
    int n;
    cout<<"请输入你需要计算长方体的个数：";
    cin>>n;
    for(int i=0;i<n;i++)
    {
        temp=i+1;
        a.set_value();
        a.show_value();
      
    }
    return 0;
}