read objects from file

I have this code:

#include <fstream>
#include <iostream>
using namespace std;

class Student
{
public:
    char   FullName[40];
    char   CompleteAddress[120];
    char   Gender;
    double Age;
    bool   LivesInASingleParentHome;
};

int main()
{
    Student one;
    strcpy(one.FullName, "Ernestine Waller");
    strcpy(one.CompleteAddress, "824 Larson Drv, Silver Spring, MD 20910");
    one.Gender = 'F';
    one.Age = 16.50;
    one.LivesInASingleParentHome = true;

    ofstream ofs("fifthgrade.ros", ios::binary);

    ofs.write((char *)&one, sizeof(one));

    Student three;
    strcpy(three.FullName, "three Waller");
    strcpy(three.CompleteAddress, "three 824 Larson Drv, Silver Spring, MD 20910");

    three.Gender = 'M';
    three.Age = 17;
    three.LivesInASingleParentHome = true;

    //ofstream ofs("fifthgrade.ros", ios::binary);

    ofs.write((char *)&three, sizeof(three));*/
    Student two;

        ifstream ifs("fifthgrade.ros", ios::binary);
    while(!(ifs.eof())){
    ifs.read((char *)&two, sizeof(two));

    cout << "Student Information\n";
    cout << "Student Name: " << two.FullName << endl;
    cout << "Address:      " << two.CompleteAddress << endl;

    if( two.Gender == 'f' || two.Gender == 'F' )
        cout << "Gender:       Female" << endl;

    else if( two.Gender == 'm' || two.Gender == 'M' )
        cout << "Gender:       Male" << endl;
    else
        cout << "开发者_如何转开发Gender:       Unknown" << endl;

    cout << "Age:          " << two.Age << endl;
    if( two.LivesInASingleParentHome == true )
        cout << "Lives in a single parent home" << endl;
    else
        cout << "Doesn't live in a single parent home" << endl;


    cout << "\n";
    }
    return 0;
}

When i read from file, the last object prints twice. What should I do?

---

Try

while(ifs.read((char *)&two, sizeof(two)))

instead of

while(!(ifs.eof()))

Also try formatting your code :)

#include <fstream>
#include <iostream>

using namespace std;

class Student
{
    public:
        char   FullName[40];
        char   CompleteAddress[120];
        char   Gender;
        double Age;
        bool   LivesInASingleParentHome;
};

int main()
{
    /*Student one;
      strcpy(one.FullName, "Ernestine Waller");
      strcpy(one.CompleteAddress, "824 Larson Drv, Silver Spring, MD 20910");
      one.Gender = 'F';
      one.Age = 16.50;
      one.LivesInASingleParentHome = true;
      ofstream ofs("fifthgrade.ros", ios::binary);
      ofs.write((char *)&one, sizeof(one));
      Student three;
      strcpy(three.FullName, "three Waller");
      strcpy(three.CompleteAddress, "three 824 Larson Drv, Silver Spring, MD 20910");
      three.Gender = 'M';
      three.Age = 17;
      three.LivesInASingleParentHome = true;
    //ofstream ofs("fifthgrade.ros", ios::binary);
    ofs.write((char *)&three, sizeof(three));*/
    Student two;
    ifstream ifs("fifthgrade.ros", ios::binary);
    while(ifs.read((char *)&two, sizeof(two)))
    {
        cout << "Student Information\n";
        cout << "Student Name: " << two.FullName << endl;
        cout << "Address:      " << two.CompleteAddress << endl;
        if( two.Gender == 'f' || two.Gender == 'F' )
            cout << "Gender:       Female" << endl;
        else if( two.Gender == 'm' || two.Gender == 'M' )
            cout << "Gender:       Male" << endl;
        else
            cout << "Gender:       Unknown" << endl;
        cout << "Age:          " << two.Age << endl;
        if( two.LivesInASingleParentHome == true )
            cout << "Lives in a single parent home" << endl;
        else
            cout << "Doesn't live in a single parent home" << endl;
        cout << "\n";
    }

    return 0;
}

---

If I were guessing, and it is a good guess, it would be the feof test in the loop. It probably is detecting feof after it reads on the next line and fails to get a full record.

You should have the read in the while loop and test for inappropriate reply, or at least check for feof again after the read.

---

Well for starter you could rewrite it so the class has a serialize/deserialize method which expects an output/input stream parameter. This code is not reusable. You also want to rewrite the code for doing output std::ostream& operator<<(std::ostream& s, Student const& rhs), etc.. Your code is a big pile of censored. If you rewrite it the main logic is going to be a couple of lines and everybody who spends 30 seconds checking it can show where the problem is.