無法綁定運營商<<在CPP

Question

大師，

給出定義如下兩個類（屬性，方法和實施省略）：

struct A { friend std::ostream& operator << (std::ostream& o, const A& c); }; 
struct B { friend std::ostream& operator << (std::ostream& o, const B& c); }; 

我使用的類如下：

ln 1: A *arrayA = new A[10]; 
ln 2: B *arrayB = new B[10]; 
ln 3: /* some codes to initialize arrayA and arrayB */ 
ln 4: for (int i = 0; i < 10; i++) { std::cout << arrayA[i]; } // this work 
ln 5: for (int j = 0; j < 10; j++) { std::cout << arrayB[j]; } // this complain 

我的編譯器抱怨B級，因爲

error: cannot bind 'std::ostream {aka std::basic_ostream<char>}' lvalue 
to 'std::basic_ostream<char>&&' 

../lib/gcc/mingw32/4.6.1/include/c++/ostream:581:5 error initializing argument 1 
of 'std::basic_ostream<_CharT, _Traits>& 
std::operator<<(std::basic_ostream<_CharT, _Traits>&&, const _Tp&) 
[with _CharT = char, _Traits = std::char_traits<char>, _Tp = ClsB] 

我不知道第5行有什麼問題。註釋掉主程序的第5行給出了我的很好的彙編，這意味着我對B類的運算符< <的定義在語法上是正確的。請給任何指示和感謝。

蔭漢

• 平臺：Win 7
• MINGW32：版本2011-11-08
• GNU請3.82
• G ++版本4.6.1

[編輯1 ] 我的程序實際上有兩個以上的班級，而我所有的班級都有操作員< <過載進行調試。我對所有類都使用了相同的簽名（適當的第二個參數）。只有B類給出這個錯誤。

[編輯2] 完整版我的類：

struct CPeople { // this is class B 
int age; 
int ageGroup; 

int zipcode; 
int communityID; 
int areaID; 
int familyID; 
int contactID; 
int contactType; /* P, D, E, M, H, W */ 
int state; 
int vaccinated; /* 0 = unvac, 1 = vaccinated */ 

friend std::ostream& operator<< (std::ostream& o, const CPeople& c) 
{ 
    o << "CPeople (" << static_cast<void const *>(&c) << "): " 
     << "\tAge Group: " << c.ageGroup 
     << "\tZip Code: " << c.zipcode 
     << "\tCommunityID: " << c.communityID 
     << "\tArea ID: "  << c.areaID 
     << "\tFamily ID: " << c.familyID 
     << "\tSchool Type: " << c.contactType 
     << "\tContact ID: " << c.contactID 
     << "\tState: "  << c.state 
     << "\tVaccination: " << c.vaccinated; 
    return (o << std::endl); 
} 
}; 

struct CWorkGroup : public CContact { // this is class A 
/* to which community this member belongs */ 
std::vector<long> member_com; 
CStatistics statistics; 

friend std::ostream& operator<< (std::ostream& o, const CWorkGroup& c) 
{ 
    o << "CWorkGroup (" << static_cast<void const *>(&c) << "): "; 
    o << "avflag = " << c.avflag << "; member: " << c.size(); 
    for (int i = 0; i < c.size(); i++) 
    { 
     o << "; (" << i << " = " << c.member[i] << ")"; 
    } 
    o << std::endl; 
    return (o << c.statistics); 
} 
}; 

用法答：

​​3210

用法B（這是錯誤）：

CPeople *people_total = new CPeople[cntTotalPop]; 
for (pIdx = 0; pIdx < cntTotalPop; pIdx++) 
{ 
    std::cout << people_total[pIdx]; 
} 

Answer 1

類和結構需要以分號結束，所以在兩行的末尾添加分號：

struct A { friend std::ostream& operator << (std::ostream& o, const A& c); }; 
struct B { friend std::ostream& operator << (std::ostream& o, const B& c); };