來源：文本檔案存盤帳戶資訊串列。例如：
10041249,Mr,Vincent,Rogan,Rogan Locksmiths Ltd,Nell,5287.000000,,491.691000,
10021250,Mrs,Adele,Cunningham,Cunningham Demolition Ltd,Dr Scott,2941.000000,,273.513000,
10051251,Mr,Rodney,Shaw,Shaw Meat Packaging Ltd,Eddie,7552.000000,,740.096000,
10001252,Mrs,Christine,Nichols,Nichols Scaffolding Ltd,Brad,6723.000000,Eddie:Brad:,672.300000,
10021253,Mr,Alexander,Marshall,Marshall Chemicals Ltd,Dr Scott,1768.000000,,173.264000,
10021254,Ms,Shirley,Hagman,On Point Sportswear Ltd,Dr Scott,52.000000,,5.200000,
....
....
....
如何從 txt 檔案中提取帶有逗號分隔符的字串并將每個由逗號分隔符分隔的元素決議為類建構式？
我嘗試使用 stringstream 從每一行中提取資料。但它不起作用。我得到的 EmployeeAccount 類在下面：
#include <iostream>
#include <sstream>
#include <string>
using namespace std;
class EmployeeAccount {
private:
//member variable
string acountNumber;
string title;
string firstname;
string lastname;
string company;
string salesperson;
double purchaseValue;
string prev_salestaff;
double commission;
public:
//overload constructor
EmployeeAccount(const string& employeeAccountInfo)
{
string str;
stringstream employeeAccountStream(employeeAccountInfo);
while (getline(employeeAccountStream, str, ','))
{
stringstream sso(str);
sso >> acountNumber;
sso >> title;
sso >> firstname;
sso >> lastname;
sso >> company;
sso >> salesperson;
sso >> purchaseValue;
sso >> prev_salestaff;
sso >> commission;
}
}
//Access methods
string getAccountNumber() { return acountNumber; };
string getTitle() { return title; };
string getFirstname() { return firstname; };
string getLastname() { return lastname; };
string getCompany() { return company; };
double getPurchaseValue() { return purchaseValue; };
string getPrev_salesstaff() { return prev_salestaff; };
double getCommission() { return commission; };
string getAccountDetail() { return acountNumber " " title " " firstname " " lastname " " company;};
//Destructor
~EmployeeAccount() {};
};
測驗代碼是這樣的：
cout << testEmployee.getAccountDetail() << endl;
cout << testEmployee.getAccountNumber() << endl;
cout << testEmployee.getTitle() << endl;
cout << testEmployee.getFirstname() << endl;
cout << testEmployee.getLastname() << endl;
cout << testEmployee.getCompany() << endl;
cout << testEmployee.getPurchaseValue() << endl;
cout << testEmployee.getPrev_salesstaff() << endl;
cout << testEmployee.getCommission() << endl;
}
uj5u.com熱心網友回復：
決議 CSV 檔案是一個老話題。您將在 stackoverflow 上找到至少 100 個帶有代碼示例的答案。很多時候，您會找到具有該功能的解決方案std::getline。請閱讀此處的檔案。它可以從std::ifstream直到或直到分隔符（,在我們的例子中為逗號）讀取字符，然后將不帶逗號的結果存盤在字串中，并從流中丟棄逗號。所以，把它扔掉。字符將存盤在std::string. 如果需要數字或其他型別，我們需要使用適當的函式將字串轉換為其他型別。
示例：我們有一個由字符“1”、“2”和“3”組成的字串，即“123”。引號表示字串型別。如果我們想將此字串轉換為整數，我們可以使用例如函式std::stoi。
在您的情況下，您有 2 個雙精度值。因此，我們會將檔案的輸入拆分為字串，然后使用函式std::stod.
您還需要知道的是，通常使用兩步方法。這樣做是為了防止從一個 csv 行中提取所有字串部分而引起的潛在問題。所以，
- 我們首先閱讀完整的一行，
- 然后將該行放入 a
std::istringstream，最后 - 讀取輸入并從那里拆分 CSV。
然后，剩下的就很簡單了。只需使用std::getline您需要的所有資料。
最后但同樣重要的是，要讀取檔案，我們只需打開它，逐行讀取，創建一個“EmployeeAccount”并將其推送到std::vector
最后我們做一些除錯輸出。
請參閱以下可能的實施建議之一：
#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
class EmployeeAccount {
private:
//member variable
std::string acountNumber;
std::string title;
std::string firstname;
std::string lastname;
std::string company;
std::string salesperson;
double purchaseValue;
std::string prev_salestaff;
double commission;
public:
//overload constructor
EmployeeAccount(const std::string& employeeAccountInfo)
{
std::istringstream employeeAccountStream(employeeAccountInfo);
std::getline(employeeAccountStream, acountNumber, ',');
std::getline(employeeAccountStream, title, ',');
std::getline(employeeAccountStream, firstname, ',');
std::getline(employeeAccountStream, lastname, ',');
std::getline(employeeAccountStream, company, ',');
std::getline(employeeAccountStream, salesperson, ',');
std::string temp;
std::getline(employeeAccountStream, temp, ',');
purchaseValue = std::stod(temp);
std::getline(employeeAccountStream, prev_salestaff, ',');
std::getline(employeeAccountStream, temp, ',');
commission = std::stod(temp);
}
//Access methods
std::string getAccountNumber() const { return acountNumber; };
std::string getTitle() const { return title; };
std::string getFirstname() const { return firstname; };
std::string getLastname() const { return lastname; };
std::string getCompany() const { return company; };
double getPurchaseValue() const { return purchaseValue; };
std::string getPrev_salesstaff() const { return prev_salestaff; };
double getCommission() const { return commission; };
std::string getAccountDetail() const { return acountNumber " " title " " firstname " " lastname " " company;};
//Destructor
~EmployeeAccount() {};
};
int main() {
std::ifstream ifs{ "accounts.txt" };
if (ifs) {
// Here we will store all accounts
std::vector<EmployeeAccount> accounts{};
// Read the file line by line
std::string line{};
while (std::getline(ifs, line)) {
// Create one account by splitting the input line
EmployeeAccount account(line);
// Add the new accounts to the vector of accounts
accounts.push_back(account);
}
// Debug output. For all accounts that we read, output all data
for (const EmployeeAccount& account : accounts) {
std::cout << "\n--------------------------\n"
<< account.getAccountDetail() << '\n'
<< account.getAccountNumber() << '\n'
<< account.getTitle() << '\n'
<< account.getFirstname() << '\n'
<< account.getLastname() << '\n'
<< account.getCompany() << '\n'
<< account.getPurchaseValue() << '\n'
<< account.getPrev_salesstaff() << '\n'
<< account.getCommission() << '\n';
}
}
else
std::cerr << "\n*** Error: Could not open source file\n\n";
}
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