Question

#include <iostream>
#include <fstream>
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, const 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] << endl;
    }
    return 0;

}

由于以下错误，此程序无法编译：严重码描述项目文件线镇压国错误 C2679 二进制＆＃39;＆gt;＆gt;＆＃39;：找不到带有＆＃39; std :: string＆＃39;类型的右手操作数的运算符（或者没有可接受的转换） Project6 c：\ users \ preston freeman \ source \ repos \ jave.cpp 21

错误 C2679 二进制＆＃39;＆lt;＆lt;＆＃39 ;:找不到带有＆＃39; const std :: string＆＃39;类型的右手操作数的运算符（或者没有可接受的转换） Project6 c：\ users \ preston freeman \ source \ repos \ jave.cpp 16

错误 C2679 二进制＆＃39;＆lt;＆lt;＆＃39;：找不到运算符，该运算符采用＆＃39; InsurancePolicy＆＃39;类型的右手操作数。（或者没有可接受的转换） Project6 c：\ users \ preston freeman \ source \ repos \ jave.cpp 32

如何解决这些错误？谢谢你的时间。

Answer 1

您正在使用

ofstream outFile;

主要。但是你的运算符重载是

 friend fstream&  operator<<(fstream&, InsurancePolicy);

请注意，ofstream不是来自fstream，这就是为什么operator <<的{{1}}重载不会使fstream工作的原因ofstream }}

您只需将fstream更改为ofstream

即可

ofstream& operator<<(ofstream& out, const InsurancePolicy pol)
{
    out << pol.policyNum << " " << pol.lastName << " " << pol.value << " " << pol.premium << endl;
    return out;
}

最好通过const＆amp; amp;传递InsurancePolicy因为ofstream不会改变它，并且复制用户定义的对象可能很昂贵

ofstream& operator<<(ofstream& out, const InsurancePolicy& pol)

您可能还需要#include <string>

演示： https://ideone.com/rJiw21

程序有错误，二元运算符

1 个答案: