HelpDifferenct Between (Class) and (Struct) ???

#include <iostream>
#include <ctime>
using namespace std;


class box{      
private:
	double height,length,width;
	char label;
public:

	double volume()            
	{
		return height*width*length;
	}
	double SA()                
	{
		return 2*height*width + 2*height*length + 2*length*width;
	}
	void Increment_Height(double x)
	{
		height += x;
	}
	double Get_Height()
	{
		return height;        
	}
	
};                              
int main()
{
	srand(time(NULL));
	box me;                     
   system("pause");
   return 0;

}