c++对象大小探究

        很多人看过《深度探索C++对象模型》，但不一定都能解释清楚下面的小程序，可以试试看。
        不过无论你能不能解释，都不妨碍你使用C++。

    #include <iostream>
    using namespace std;
    class a {};
    class b{};
    class c:public a{
    virtual void fun()=0;
    };

    class d:public b,public c{virtual void fun();};

    class e: public d{int test;};
    void d::fun()
      {
      };
    class f:public a{};
    class g:public f{virtual void fun(){};};
    class h:public a,public b{};
    class i:public a,public b{char cc;char dd;char ee;char ff;void gao(){};};
    class j:public a,public b{char cc;char dd;char ee;virtual void gao(){};};
    class k:public a,public b{char cc;char dd;char ee;char ff;};
    class l:public a{char cc;char dd;char ee;char ff;};
    class m{char cc;char dd;char ee;char ff;};
    class n{char nn;};
    class o:public a,public b{};
    class p:public n,public b,public a{char pp;};
    class q{char qq;};
    class r:public a,public n,public q{};
    class s:public n,public q{};
    class t:virtual public a, virtual public b{};
    class u:virtual public b, virtual public c{};
    class v:virtual public c{ char vv;};
    class w:virtual public c{ char vv;};
    class x:virtual public v, virtual public w{};
    class y:virtual public v{ };
    class z:virtual public y,virtual public x{ };

    int main()
    {
    a aa;
    b bb;

    d dd;
    e ee;
    f ff;
    g gg;
    h hh;
    i ii;
    j jj;
    k kk;
    l ll;
    m mm;
    n nn;
    o oo;
    p pp;
    q qq;
    r rr;
    s ss;
    t tt;

    a * pa=&aa;
    b * pb=&bb;
    d * pd=&dd;
    e * pe=&ee;
    f * pf=&ff;
    g * pg=&gg;
    h * ph=&hh;
    i * pi=&ii;
    j * pj=&jj;
    k * pk=&kk;
    l * pl=&ll;
    m * pm = &mm;
    n * pn =&nn;
    o * po = & oo;
    q * pq=&qq;
    r * pr=&rr;
    cout<<\"sizeof(a)\"<<sizeof(a)<<endl;
    cout<<\"sizeof(b)\"<<sizeof(b)<<endl;
    cout<<\"sizeof(c)\"<<sizeof(c)<<endl;
    cout<<\"sizeof(d)\"<<sizeof(d)<<endl;
    cout<<\"sizeof(e)\"<<sizeof(e)<<endl;
    cout<<\"sizeof(f)\"<<sizeof(f)<<endl;
    cout<<\"sizeof(g)\"<<sizeof(g)<<endl;
    cout<<\"sizeof(h)\"<<sizeof(h)<<endl;
    cout<<\"sizeof(i)\"<<sizeof(i)<<endl;
    cout<<\"sizeof(j)\"<<sizeof(j)<<endl;
    cout<<\"sizeof(k)\"<<sizeof(k)<<endl;
    cout<<\"sizeof(l)\"<<sizeof(l)<<endl;
    cout<<\"sizeof(m)\"<<sizeof(m)<<endl;
    cout<<\"sizeof(n)\"<<sizeof(n)<<endl;
    cout<<\"sizeof(o)\"<<sizeof(o)<<endl;
    cout<<\"sizeof(p)\"<<sizeof(p)<<endl;
    cout<<\"sizeof(q)\"<<sizeof(q)<<endl;
    cout<<\"sizeof(r)\"<<sizeof(r)<<endl;
    cout<<\"sizeof(s)\"<<sizeof(s)<<endl;
    cout<<\"sizeof(t)\"<<sizeof(t)<<endl;
    cout<<\"sizeof(u)\"<<sizeof(u)<<endl;
    cout<<\"sizeof(v)\"<<sizeof(v)<<endl;
    cout<<\"sizeof(w)\"<<sizeof(w)<<endl;
    cout<<\"sizeof(x)\"<<sizeof(x)<<endl;
    cout<<\"sizeof(y)\"<<sizeof(y)<<endl;
    cout<<\"sizeof(z)\"<<sizeof(z)<<endl;
    return   0;

    }
    不要看答案，自己写出来。答案在下一页

    [Page]

    a 1
    b 1
    c 4
    d 8
    e 12
    f 1
    g 4
    h 1
    i 5
    j 8
    k 5
    l  4
    m 4
    n  1
    o 1
    p  3
    q  1
    r  2
    s  2
    t  8
    u 12
    v 12
    w 12
    x 24
    y 16
    z 32