这个为什么会出现不能读取内存的情况

Question

今天按书上写Josephus的一个解法的程序，但是碰到了无法读取内存的问题

这个是主函数
#include"jose.h"   
#include<iostream>
using namespace std;
int main(){
  Jose jose;     
  jose.Initial();
  jose.GetWinner();
}

这个是ring.cpp，问题就是在这里，pCurrent和pivot显示无法读取内存
#include"ring.h"
#include<iostream>
#include<iomanip>
using namespace std;
Ring::Ring(int n, int beg){
  pBegin = new Boy[n];         
  pCurrent = pBegin;
  for(int i=1; i<=n; i++){
    pBegin[i-1].next = pBegin+i%n;      
    pBegin[i-1].code=i;       
    PutBoy();
    pCurrent = pCurrent->next;
  }
  pCurrent = &pBegin[n + beg - 2];
}
void Ring::Count(int m)
{
  for(int i=1; i<=m; i++)
  {
    pivot = pCurrent;
    pCurrent = pCurrent->next;
  }
}
void Ring::PutBoy(bool f) const{
  static int numInLine;
  if(f){   
    numInLine = 0;
    return ;
  }
  if(numInLine++%10==0)
    cout<<endl;
  cout<<setw(4)<<pCurrent->code;
}
void Ring::ClearBoy(){
  pivot->next=pCurrent->next;
}
Ring::~Ring(){
  delete[] pBegin;
}
void Ring::Display() {
    for (Boy* pBegin = pCurrent; (pCurrent = pCurrent->next) != pBegin;)
        PutBoy(0);
    PutBoy(1);
}

这个是ring.h
#ifndef RING
#define RING
struct Boy{                   
  int code;
  Boy* next;
};
class Ring{                   
public:
  Ring(int n, int beg);
  void Count(int m);           
  void PutBoy(bool f=0)const;        
  void ClearBoy();             
  void Display();
 ~Ring();
private:
  Boy* pBegin;
  Boy* pivot ;
  Boy* pCurrent;
};
#endif

下面是另外两个文件

这个是jose.cpp
#include"ring.h"    
#include"jose.h"
#include<iostream>
#include<cstdlib>   
using namespace std;
//---------------------
void Jose::Initial(){
  int num,begin,m;
  cout<<"please input the number of boys," \
        "begin position,interval per count :\n";
  cin>>num>>begin>>m;
  if(num<2){
    cerr<<"bad number of boys\n";
    exit(1);
  }
  if(begin<0){
    cerr<<"bad begin position.\n";
    exit(1);
  }
  if(m<1||m>num){
    cerr<<"bad interval number.\n";
    exit(1);
  }
  numOfBoys=num;
  beginPos=begin;
  interval=m;
}//--------------------
void Jose::GetWinner(){
  Ring x(numOfBoys,beginPos);      
  for(int i=1; i<numOfBoys; i++){  
    x.Count(interval);   
    x.PutBoy(0);         
    x.ClearBoy();        
  }
  x.Count(1);
  cout<<"\nthe winner is ";
  x.PutBoy(0);  
  cout<<"\n";
}//--------------------

这个是jose.h
#ifndef JOSE
#define JOSE
class Jose{
public:
  Jose(int boys=10, int begin=1, int m=3){
    numOfBoys=boys;
    beginPos=begin;
    interval=m;
  }
  void Initial();
  void GetWinner();
private:
  int numOfBoys;
  int beginPos;
  int interval;
};//-------------------
#endif