#include<iostream>
using namespace std;
struct bop
{
       char fullname[20];
       char title[20];
       char bopname[20];
       int preference;
}
int main()
{
    bop arry[5];
    bop arry[1]={Wimp Macho,Wimp Macho,gou,1};
    bop arry[2]={Raki Rhodes,Junior Programmer,mao,2};
    bop arry[3]={Hoppy Hipman,MIPS,yu,3};
    bop arry[4]={Celia laiter,Analyst Trainee,xiong,2};
    bop arry[5]={Ydsha Sjfdl,DJFA alf,zhu,1};
   
    cout<<"Benevolent Order of Programmers Report\n";
    cout<<"a. display by name        b. display by title\n";
    cout<<"c. display by bopname     d. display by preference\n";
    cout<<"q. auit";
    cout<<"Enter your choice:";
    char ch;
    cin.get(ch);
   
    int i;
    for(i=1;i<=5;i++)
    {
       switch(ch)
       {
           case'a':cout<<arry[i].fullname<<"\n";break;
           case'b':cout<<arry[i].title<<"\n";break;
           case'c':cout<<arry[i].bopname<<"\n";break;
           case'd':if(arry[i].preference=='1'
                     cout<<arry[i].fullname<<"\n";break;
                     else if(arry[i].preference=='2'
                     cout<<arry[i].title<<"\n";break;
                     else if(arry[i].preference=='3'
                     cout<<arry[i].bopname<<"\n";break;
           case'q':cout<<"quit\n";break;
           defaut:cout"it is wrong";
       }
     }
   system("pause");
   return 0:
}
还有如果要在switch之后再次回到cin.get()也就是说可以多次输入输出怎么办

想循环输入你可以吧switch(ch)改为switch（cin.getch(ch)）,把break改为continue
这里if(arry[i].preference=='1'）少了个括号
这里应该加大括号，不然else就不执行了（我想是的，你试试看吧）
if(arry[i].preference=='1'）
                     {cout<<arry[i].fullname<<"\n";break;}
                     else if(arry[i].preference=='2'
                     {cout<<arry[i].title<<"\n";break;}
}                     else if(arry[i].preference=='3'
                     cout<<arry[i].bopname<<"\n";break;

除非必要，几无改动，仅是修正你的错误

#include <iostream>
using namespace std;

struct bop
{
    char fullname[20];
    char title[20];
    char bopname[20];
    int preference;
};

int main()
{
    bop arry[5] = { { "Wimp Macho",   "Wimp Macho",        "gou",   1 }
                  , { "Raki Rhodes",  "Junior Programmer", "mao",   2 }
                  , { "Hoppy Hipman", "MIPS",              "yu",    3 }
                  , { "Celia laiter", "Analyst Trainee",   "xiong", 2 }
                  , { "Ydsha Sjfdl",  "DJFA alf",          "zhu",   1 } };

    cout << "Benevolent Order of Programmers Report\n"
            "a. display by name        b. display by title\n"
            "c. display by bopname     d. display by preference\n"
            "q. quit\n"
            "Enter your choice:" << flush;

    for( char ch; cin>>ch; )
    {
        if( ch == 'q' )
        {
            cout << "quit" << endl;
            break;
        }
        if( ch<'a' || ch>'d' )
        {
            cout << "it is wrong" << endl;
            continue;
        }

        for( int i=0; i<5; ++i )
        {
            const bop& ref = arry[i];

            switch( ch )
            {
            case 'a':
                cout << ref.fullname << endl;
                break;
            case 'b':
                cout << ref.title << endl;
                break;
            case 'c':
                cout << ref.bopname << endl;
                break;
            case 'd':
                if( ref.preference == 1 )
                    cout << ref.fullname << endl;
                else if( ref.preference == 2 )
                    cout << ref.title << endl;
                else if( ref.preference == 3 )
                    cout << ref.bopname << endl;
                break;
            }
        }
    }

    return 0;
}