设计一个立方体类

题目要求：设计一个Box类，它能计算并输出立方体的体积和表面积。

#include<stdio.h>#include<iostream>#include<string>using namespace std;class Box{public:    void SetA(double a);    double GetVolume();    double GetArea();private:    double m_a; // 立方体边长};void Box::SetA(double a){    m_a = a;}double Box::GetArea(){    return 6 * m_a; //表面积}double Box::GetVolume(){    return m_a * m_a * m_a; //体积}int main(){    Box a,b;    a.SetA(0.0);    b.SetA(5.0);    cout<<a.GetArea()<<" "<<a.GetVolume()<<endl;    cout<<b.GetArea()<<" "<<b.GetVolume()<<endl;    return 0;}