c++继承这里怎么改，求指导

Question

 [Error] 'a' was not declared in this scope

[Error] 'b' was not declared in this scope

每个构造函数都这样报错

#include <iostream>
using namespace std;
class Container{
	protected:
		double s,v,h;
	public:
		virtual void out(){
			cout<<"s="<<s<<"v="<<s*h;
		}
		Container(double a,double b){
			s=a;
			h=b;
			v=s*h;
		}
};
class Sphere:public Container{
	private:
		double r;
	public:
		virtual void out(){
			s=4*3.1415926*r*r;
			v=s*r/3;
			cout<<"s="<<s<<"v="<<v;
		}
		Sphere(double i):Container(a,b){
			r=i;
		}
};
class Cylinder:public Container{
	private:
		double r;
	public:
		virtual void out(){
			s=2*3.1415926*r*r+2*3.1415926*r*h;
			v=h*3.1415926*r*r;
		    cout<<"s="<<s<<"v="<<v;
		}
		Cylinder(double m):Container(a,b){
			r=m;
		}
};
class Cube:public Container{
	private:
		double l;
	public:
	   	virtual void out(){
			s=6*l*l;
			v=l*l*l;
		    cout<<"s="<<s<<"v="<<v;
		}
		Cube(double n):Container(a,b){
			l=n;
		}
};
int main() {
	return 0;
}

题目：写一个程序，定义抽象基类Container，由它派生出3个派生类Sphere(球体)、Cylinder(圆柱体)、Cube(正方体)。用虚函数分别计算几种图形的表面积和体积。

Answer 1

子类构造函数调用基类构造函数传递的a和b从哪来的?