C++ 文件 I/O 我无法读取 .dat 文件

Question

using namespace std;

struct WebSites
{
    string siteName;
    int rank;

    string getSiteName() { return siteName; }
    int getRank() { return rank; }
    WebSites(string const&, int);
    WebSites();
};

WebSites::WebSites(string const& siteName, int rank) {
    this->siteName = siteName;
    this->rank = rank;

}

WebSites::WebSites() {}

ostream& operator << (ostream& stream, WebSites const& data) {
    stream << data.rank << " " << data.siteName.size() << " " << data.siteName<< endl;
    return stream;

}

istream& operator >> (istream& stream, WebSites data) {
    stream >> data.siteName >> data.rank;
    return stream;

}


int main() {

    WebSites s1("www.google.co.uk", 1);

    //write to file

    ofstream writer("chou.dat", ios::out | ios::binary); //i'll add ios::app later
    if (!writer) {
        cout << " error opening file " << endl;
        return -1;
    }
    else {
        writer << s1.getSiteName() << " " << s1.getRank() << endl;
    }
    writer.close();

    //read file
    fstream writerR("chou.dat", ios::binary | ios::in | ios::ate);
    WebSites read;
    while (writerR >> read) {

        cout << read.siteName << " rank: "<< read.rank << endl;
    }
    writerR.close();
    return 0;
}

有人能告诉我为什么这个程序不能读取和显示控制台文件吗？？？我的意思是它写得很完美。我尝试更改内容，但没有任何效果我在网上检查了类似的代码，但仍然没有。

Answer 1

有一些问题:

1. 根据 docs指定 ios::ate 会

   seek to the end of stream immediately after open

   所以根本没有什么可读的，你的 while 循环将永远不会进入。

2. 另一个问题在这里:operator >> (istream& stream, WebSites data)

   您的运算符(operator)正在用数据填充拷贝。解决这个第二个参数应该是一个引用:

   operator >> (istream& stream, WebSites& data)