高手帮忙看看这段代码有啥问题？

int Addbook()
{  
    int i,c;
    Book p;
    Book list[maxbook];
    int j=-1;   

    fstream iofile;
    ifstream infile;
    ofstream outfile;
   
    loop:cout<<"请输入需要添加图书名称：";
    cin>>p.bname;cout<<endl;                //输入书名
    do
    {
      cout<<"请输入图书的五位数编号：";
      cin>>p.bid;cout<<endl;                //输入书的ID号
    }while(p.bid<10000||p.bid>99999);      //检查ID号的合法性
   
    cout<<"请输入需要添加图书作者：";
    cin>>p.bauthor;cout<<endl;              //输入作者
    cout<<"请输入添加的图书出版社：";
    cin>>p.bpublisher;cout<<endl;           //输入出版单位
    do
    {
      cout<<"请输入图书的关键字A-Z：";
      cin>>p.bkeyword;cout<<endl;          //设置书的关键字
    }while(p.bkeyword<65||p.bkeyword>90);

    do
    {
      cout<<"请输入要添加图书的数量：";
      cin>>p.bsum;cout<<endl;              //输入数的数量
    }while(p.bsum<=0);               

        do
    {
      cout<<"输入数字1确认此书信息：";
      cin>>p.flag;cout<<endl;
    }while(p.flag!=1);                        //确认输入数的信息
   
   
    iofile.open("booksum.txt",ios::in|ios::binary);   //以输入方式打开当前书目数量文件
     if(!iofile)
    {   
        cerr<<"打开失败"<<endl;
        iofile.open("booksum.txt",ios::out);         //file doesn't exist,create a new one
        booksum=0;
    }
    else
    {   
         iofile.close();
         iofile.open("booksum.txt",ios::in|ios::binary);
         iofile>>booksum;
    }
    iofile.close();
    c=booksum;   
   
    if(c==0)
    {   
        cout<<"当前书库有"<<c<<"本图书"<<endl;
        cout<<"你所添加的书目信息为："<<endl;
        cout<<"图书名称："<<p.bname<<endl;
        cout<<"图书编号："<<p.bid<<endl;
        cout<<"图书作者："<<p.bauthor<<endl;
        cout<<"图书出版社："<<p.bpublisher<<endl;
        cout<<"图书数量："<<p.bsum<<endl;
   
        iofile.open("book.txt",ios::in);            //以输入，输出方式打开book.txt
        if(!iofile)
            {
                 iofile.open("book.txt",ios::out); //file doesn't exist,create a new one
                 iofile.close();
                 iofile.open ("book.txt",ios::in|ios::out|ios::binary);
             }
        else
        {  iofile.close();
           iofile.open("book.txt",ios::in|ios::out|ios::binary);
        }
        iofile.seekp(0,ios::beg);
        iofile.write((char*)&p,sizeof(p));
        iofile.close();
        outfile.open("booksum.txt",ios::out);
        booksum=booksum+1;
        outfile<<booksum;
        outfile.close();

    }

     else
         
    {   cout<<"当前书库有"<<c<<"本图书"<<endl;
        iofile.open("book.txt",ios::in|ios::out|ios::binary);
           for(i=0;i<c;i++)
       {iofile.seekg(i*sizeof(list[i]),ios::beg);
      iofile.read((char*)&list[i],sizeof(list[i]));
      if(p.bid==list[i].bid)
        {j=i;
         break;}
           }
           iofile.close();


        if(j==-1)
       {   
        cout<<"你所添加的书目信息为："<<endl;
        cout<<"图书名称："<<p.bname<<endl;
        cout<<"图书编号："<<p.bid<<endl;
        cout<<"图书作者："<<p.bauthor<<endl;
        cout<<"图书出版社："<<p.bpublisher<<endl;
        cout<<"图书数量："<<p.bsum<<endl;
        iofile.open("book.txt",ios::in|ios::out|ios::binary);
        iofile.seekp(0,ios::end);
        iofile.write((char*)&p,sizeof(p));
        iofile.close();
        outfile.open("booksum.txt",ios::out);
        booksum=booksum+1;
        outfile<<booksum;
        outfile.close();
        
        }
      else if(j>=0)
        {   cout<<"你所输入图书编号已存在，该书目将合并入此记录"<<endl;
           Book book;
           list[j].bsum=list[j].bsum+p.bsum;
           iofile.open("book.txt",ios::in|ios::out|ios::binary);
           iofile.seekg(j*sizeof(book),ios::beg);
           iofile.read((char*)&book,sizeof(book));
           book.bsum=list[j].bsum;
           iofile.seekp(j*sizeof(book),ios::beg);
           iofile.write((char*)&book,sizeof(book));
           iofile.close();
           }
      else cerr<<"出现错误"<<endl;
    }