c++ - 如何在 vector 元素中找到结构数据？

Question

我正在从事客户端/服务器项目。我正在努力解决如何在数据库中找到 vector 的信息以匹配请求的客户帐号。

头文件

struct storeData
{
    int iAccountNumber;
    int iPin;
    double dBalance;
    string sFirstName;
    string sLastName;
    string sMiddleInitial;
};
vector <storeData> storeDataArray;
storeData dataObj;

---

在服务器文件中..

int MyThread::findAccountNumberInStore(int iAccountNumber)
{
    int iIndex = -1;

    for(int unsigned i = 0; i <= storeDataArray.size(); i++)
    {
         //i got error message in if statement. i dont know how to fix it.
        if(iAccountNumber == storeDataArray.at(dataObj.iAccountNumber))
        {
              return i;
        }

    }
    return iIndex; //no account is found...
}

---

另外，如何将结构的数据存储在 vector 中(所有数据都在一个元素中)？

Answer 1

来自 vector.at 的描述:

Returns a reference to the element at position n in the vector.

The function automatically checks whether n is within the bounds of valid elements in the vector, throwing an out_of_range exception if it is not (i.e., if n is greater or equal than its size). This is in contrast with member operator[], that does not check against bounds.

您可以在此处阅读有关此功能的更多信息: vector.at

你也可以在这里阅读关于它的讨论: vector::at vs. vector::operator[]

对于你的实际问题，我建议这样使用它:

if(iAccountNumber == storeDataArray.at(i).iAccountNumber)