以下程序的运行结果是()
#include<iostream> using namespace std; class A{ public: void set(int I,int j) { x=i; y=j; } int get_y() { return y; } private: int x,y; }; class box { public: void set(int l,int w,int s,int p) { length=l; width=w; label.set(s,p); } int get_area() { return length*width; } private: int length,width; A label; }; int main() { box b; b.set(4,6,1,20); cout<<b.get_area()<<endl; return 0; }