在C++ 98中，'dvd1'必須由構造函數初始化，而不是'{...}'

如何初始化dvd1？在C++ 98中，'dvd1'必須由構造函數初始化，而不是'{...}'

C:\Users\SuperUser\Google Drive>g++ -o a Question1.cpp

Question1.cpp: In function 'int main()':

Question1.cpp:39:76: error: in C++98 'dvd1' must be initialized by constructor, not by '{...}'

dvd dvd1 = {"Zombie","BBC","James","English","Alw",2012,20170601,20170630};

#include <iostream> 
#include <string> 

using namespace std; 

class dvd 
{ 
    string movieName,movieProdComp,movieLeadActor,movieLanguage,renterName; 
    int releaseYear,rentDate,returnDate; 
    public: 

     dvd(string mn,string mpc,string mla,string ml, string rn,int ry,int rd,int retd); 
     void print(); 
}; 

dvd::dvd(string mn,string mpc,string mla,string ml, string rn, int ry,int rd,int retd){ 
    movieName=mn; 
    movieProdComp=mpc; 
    movieLeadActor=mla; 
    movieLanguage=ml; 
    renterName=rn; 
    releaseYear=ry; 
    rentDate=rd; 
    returnDate=retd; 
} 

void dvd::print(){ 
    cout<<"Movie:"<<movieName<<endl; 
    cout<<"Production:"<<movieProdComp<<endl; 
    cout<<"Starring:"<<movieLeadActor<<endl; 
    cout<<"Language:"<<movieLanguage<<endl; 
    cout<<"Rented By:"<<renterName<<endl; 
    cout<<"Released:"<<releaseYear<<endl; 
    cout<<"Rent Date:"<<rentDate<<endl; 
    cout<<"Return Date:"<<returnDate<<endl; 
} 

int main(){ 
    dvd(); 
    dvd dvd1 = {"Zombie","BBC","James","English","Alw",2012,20170601,20170630}; 
    dvd1.print(); 
}

來源

2017-07-10 null

這就是所謂的list initialization，以及非聚合類型它僅支持C++ 11：

dvd dvd1 = {"Zombie","BBC","James","English","Alw",2012,20170601,20170630};

對於C++ 98，你可能想要改變一點，像往常一樣打電話給建設者：

dvd dvd1("Zombie","BBC","James","English","Alw",2012,20170601,20170630);

來源

2017-07-10 08:45:35 iehrlich

謝謝。我會在9分鐘內接受這個答案。 – null

Nit：僅支持C++ 11中具有顯式構造函數*的類。 C++ 98可以通過'struct simple {int i，j; } value = {0，1};' –

@MartinBonner謝謝，我添加了關於正確構造函數的註釋。關於struct初始化，我的*個人意見*是省略這樣的通知。 C++ *希望結構是類，所以我們不要談論它失敗的時刻* :) – iehrlich

dvd是非aggregate type，它不能用支撐初始化器初始化，直到C++ 11支持list initialization。（更準確地說，你正在試圖做的是複製列表初始化。）

對於C++ 98，你可以寫

dvd dvd1 ("Zombie","BBC","James","English","Alw",2012,20170601,20170630); 
dvd dvd1 = dvd("Zombie","BBC","James","English","Alw",2012,20170601,20170630);

在C++ 98可以使用aggregate initialization像dvd dvd1 = {...};只有當它是一個聚合類型;對於這種情況dvd有一個用戶定義的構造函數，然後它不會。

來源

2017-07-10 09:10:51 songyuanyao

在C++ 98中，'dvd1'必須由構造函數初始化，而不是'{...}'

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