簡單的C++控制檯I/O問題

Question

#include <iostream> 
using namespace std; 

const int Max=20; 

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

int main() 
{ 
    bop a[5]= 
    { 
     {"Steve Jobs", "BFF", "Rita",0}, 
     {"Bill Gates", "BFF2", "Ann",1}, 
     {"Mark", "BFF3", "Boss", 2}, 
     {"Edward", "BFF4", "Jiezha", 2}, 
     {"Larry Page", "BFF5", "Michele", 1} 
    }; 
    cout << "Benevolent Order of Programmers Report\n"; 
    cout << "a. display by name   b. display by title\n" 
      "c. display by bopname  d. display by preference\n" 
      "q. quit\n" 
      "Enter your choice: "; 
    char ch; 
    (cin >> ch).get(); 
    int i; 
    while (ch!='q') 
    { 
     switch (ch) 
     { 
      case 'a': for (i=0; i<Max; i++) cout << a[i].fullname << endl; break; 
      case 'b': for (i=0; i<Max; i++) cout << a[i].title << endl; break; 
      case 'c': for (i=0; i<Max; i++) cout << a[i].bopname << endl; break; 
      case 'd': for (i=0; i<Max; i++) 
         switch (a[i].preference) 
         { 
          case 0: cout << a[i].fullname << endl; break; 
          case 1: cout << a[i].title << endl; break; 
          case 2: cout << a[i].bopname << endl; break; 
         } 
         break; 
     } 
     cout << "Next choice: "; 
     (cin >> ch).get(); 
    } 
    cout << "Bye!" << endl; 
    return 0; 
} 

此程序會顯示大量垃圾如下：

Benevolent Order of Programmers Report 
a. display by name   b. display by title 
c. display by bopname  d. display by preference 
q. quit 
Enter your choice: a 
Steve Jobs 
Bill Gates 
Mark 
Edward 
Larry Page 
^?&i? 
'=YV? 
K>YV? 
f?YV? 
??YV? 
xterm-256color 
11dry7st9vkb200000gn/T/ 
T3PDw/Render 
anguage (C++) 
B6 
qUSg/Listeners 
Message=/tmp/launch-Gpgr3C/Apple_Ubiquity_Message 
/bin:/usr/sbin:/sbin:/usr/local/bin 
ge (C++)/cpp 
boris 
Next choice: 

可有人向我解釋原因，並告訴我如何糾正這一計劃？我也嘗試用cin >> ch替換（cin >> ch）.get（）。它也不起作用。非常感謝！

Answer 1

問題出在你的內部實現中。你做到以下幾點：

case 'a': for (i=0; i<Max; i++) cout << a[i].fullname << endl; break; 
//case 'b': ... 

如果你頂一下，最大的定義爲20：

const int Max=20; 

但你的陣列只中有5名成員：

bop a[5]= 
{ 
    {"Steve Jobs", "BFF", "Rita",0}, 
    {"Bill Gates", "BFF2", "Ann",1}, 
    {"Mark", "BFF3", "Boss", 2}, 
    {"Edward", "BFF4", "Jiezha", 2}, 
    {"Larry Page", "BFF5", "Michele", 1} 
}; 

所以當它打印索引6-19的值時，它會打印垃圾。計算垃圾行數加上正確輸出的行數。完美20.

Answer 2

它看起來像你迭代超出數組的界限。爲什麼你迭代到20（MAX）？相反，您應該重複5次。

此外，你應該在你的問題中包括你的預期輸出是什麼。