而它会两次执行While循环吗？

Question

我尝试解析一个名为FileName的文本文件，如下所示：

KD JD 6s 5s 3c // no rank (king high)
AH Ks Js AD Ac // three of a kind

现在我想将它们存储到一个向量中(“//”之前的所有内容)。

int FileParsing(vector<Card> & v, char * FileName) {
    ifstream ifs;
    ifs.open(FileName);
    if (!ifs.is_open()){
        cout << "file cannot be opened." << endl;
    } else {        
        string line;                    
        while(getline(ifs, line)){
            istringstream iss (line); 
            bool condition = CountWords(line); //dont worry about this method   
            ReadCardDefinitionStrings (condition, line, v);
        }       
    }
    return 0;
}


void ReadCardDefinitionStrings (bool condition, string line, vector<Card> & v){
    istringstream iss (line);   
    string CardDefinitionStrings;   //e.g. 2C, 3h, 7s, Kh
    if (condition) {
            while(iss>>CardDefinitionStrings){  
            if (CardDefinitionStrings == "//"){ //stop reading after it sees "//"
                return;
            }
            Card c = TestCard(CardDefinitionStrings);
            v.push_back(c);     
        }
    }
}

我遇到的问题是:当它在3c之后看到"//“时，它会返回到

    while(getline(ifs, line)){
        istringstream iss (line); 
        bool condition = CountWords(line);  
        ReadCardDefinitionStrings (condition, line, v);
    }

但这一次，行是空的(我希望它是: AH Ks Js AD Ac // three of a Ks)，这意味着这个循环只运行一次，不做任何事情。下一次运行时，行等于AH，Ks，Js，AD，Ac //三种类型。知道为什么会这样吗？

Answer 1

我想你忘了写很多代码了(卡片定义之类的)。而且，据我所知，在某些地方有几个多余的定义。

但是，我已经实现了您想要的功能(能够解析一个名为FileName的文本文件，如下所示)：

KD JD 6s 5s 3c // no rank (king high)
AH Ks Js AD Ac // three of a kind

假设已经使用Filename初始化了输入文件流：

ifstream ifs(FileName);

if (!ifs.is_open()) {
    cout << "file cannot be opened." << endl;
}
else {
    string line;

    //getline reads up until the newline character
    //but you want the characters up to "//"
    while(std::getline(ifs, line)) {

        //line has been read, now get rid of the "//"
        string substr = line.substr(0,line.find("//"));

        //assign the substr to an input stringstream
        istringstream iss(substr);

        //this will hold your card
            //NOTE: Since I don't have your implementation of Card, I put it as a string instead for demonstration purposes
        string card;

        //keep reading until you've read all the cards in the substring (from line)
        while (iss >> card) {
            v.push_back(card);//store the card in the vector
            cout << card << endl;//now output it to verify that the cards were read properly
        }

        cout << endl;//this is just for spacing - so it'll help us distinguish cards from different lines (in the output)
    }
    ifs.close();
}

输出：

KD
JD
6s
5s
3c

AH
Ks
Js
AD
Ac

这就是你想要的。;)