使用fstream的程序將不合規

Question

#include<iostream>
#include<fstream>
#include<string>
#include<iomanip>
using namespace std;
class InsurancePolicy
{
    friend fstream&  operator<<(fstream&, InsurancePolicy);
    friend istream& operator>>(istream&, InsurancePolicy&);
private:
    int policyNum;
    string lastName;
    int value;
    int premium;
};
fstream& operator<<(fstream& out, InsurancePolicy pol)
{
    out << pol.policyNum << " " << pol.lastName << " " << pol.value << " " << pol.premium << endl;
    return out;
}
istream& operator>>(istream& in, InsurancePolicy& pol)
{
    in >> pol.policyNum >> pol.lastName >> pol.value >> pol.premium;
    return in;
}
int main()
{
    ofstream outfile;
    outFile.open("Policy.txt");
    Policy aPolicy[10];
    for (int count = 0; count < 10; ++count)
    {
        printf("Enter the policy number, the holder's last name, the value, and the premium.");
        cin >> aPolicy[count];
        outfile << aPolicy[count] << endl;
    }

}此程序應從鍵盤接受值並將它們打印到文件中。 但是，它給出了許多語法錯誤。

嚴重性代碼說明項目文件行抑制狀態錯誤C2065'outFile'：未聲明的標識符Project6 c：\\ users \\ preston freeman \\ source \\ repos \\ jave.cpp 39

錯誤'.open'左邊的錯誤C2228必須具有class / struct / union Project6 c：\\ users \\ preston freeman \\ source \\ repos \\ jave.cpp 39

錯誤C2065“政策”：未聲明的標識符Project6 c：\\ users \\ preston freeman \\ source \\ repos \\ jave.cpp 40

錯誤C2146語法錯誤：缺少';' 標識符'aPolicy'Project6之前c：\\ users \\ preston freeman \\ source \\ repos \\ jave.cpp 40

錯誤C2065'aPolicy'：未聲明的標識符Project6 c：\\ users \\ preston freeman \\ source \\ repos \\ jave.cpp 40

錯誤C2065'aPolicy'：未聲明的標識符Project6 c：\\ users \\ preston freeman \\ source \\ repos \\ jave.cpp 44

錯誤C2065'aPolicy'：未聲明的標識符Project6 c：\\ users \\ preston freeman \\ source \\ repos \\ jave.cpp 45

如何解決這些錯誤？ 感謝您的時間？

Answer 1

代碼中有很多錯別字，但是主要的問題是從fstream到ofstream沒有已知的轉換，因此這是代碼的正確版本：

#include <iostream>
#include <fstream>
using namespace std;
class InsurancePolicy
{
    friend ofstream&  operator<<(ofstream&, InsurancePolicy);
    friend istream& operator>>(istream&, InsurancePolicy&);
private:
    int policyNum;
    string lastName;
    int value;
    int premium;
};
ofstream& operator<<(ofstream& out, InsurancePolicy pol)
{
    out << pol.policyNum << " " << pol.lastName << " " << pol.value << " " << pol.premium << endl;
    return out;
}
istream& operator>>(istream& in, InsurancePolicy& pol)
{
    in >> pol.policyNum >> pol.lastName >> pol.value >> pol.premium;
    return in;
}
int main() {
    ofstream outFile;
    outFile.open("Policy.txt");
    InsurancePolicy aPolicy[10];
    for (int count = 0; count < 10; ++count)
    {
        printf("Enter the policy number, the holder's last name, the value, and the premium.");
        cin >> aPolicy[count];
        outFile << aPolicy[count]<<std::endl;
    }
    return 0;

}