Thread: File Input from structue???

This will work. I don't know how to do it using c++ streams though. You have to open the file in binary mode and read a chunk of data the size of your structure. If you pass fread() a pointer to your structure it will populate your structure (assuming the file has the correct format).

Code:

int main(int argc, char *argv[])
{
    FILE * sFile;
    struct data student[10];
    
    if (NULL == (sFile = fopen("student.data", "rb")))
    {
        cout << "Could not open file" << endl;
        system("PAUSE");
        return -1;
    }
    cout << "name\tsex\tage\tweight:" << endl;
    for (int i=0; i<10; i++)
    {
        fread(&student[i], sizeof(data), 1, sFile);
        cout << student[i].name << "\t";
        student[i].MF?(cout << "female\t"):(cout << "male\t");     
        cout << student[i].age << "\t" << student[i].weight << endl;
    }
    system("PAUSE");
    return EXIT_SUCCESS;
}

kyle

Thanks for the info. So heres the revised example which contains both the c method and the c++ file stream method:

Code:

#define USE_STREAMS

enum sex {male, female};
struct data
{
	char name[30];
	sex MF;
	int age;
	double weight;
};

using namespace std;
int main(int argc, char *argv[])
{
    int length;
    struct data student[10];
    
    #ifdef USE_STREAMS
    ifstream isFile;
    isFile.open ("student.data", ios::binary );

    isFile.seekg (0, ios::beg);
    // read data 
    for (int i=0; i<10; i++)
    {            
        isFile.read ((char *)(&student[i]),sizeof(data));
    }
    isFile.close();
    cout << "name\tsex\tage\tweight:" << endl;
    for (int i=0; i<10; i++)
    {
        cout << student[i].name << "\t";
        student[i].MF?(cout << "female\t"):(cout << "male\t");     
        cout << student[i].age << "\t" << student[i].weight << endl;
    }
    #else
    FILE * sFile;
     
    if (NULL == (sFile = fopen("student.data", "rb")))
    {
        cout << "Could not open file" << endl;
        system("PAUSE");
        return -1;
    }
    cout << "name\tsex\tage\tweight:" << endl;
    for (int i=0; i<10; i++)
    {
        fread(&student[i], sizeof(data), 1, sFile);
        cout << student[i].name << "\t";
        student[i].MF?(cout << "female\t"):(cout << "male\t");     
        cout << student[i].age << "\t" << student[i].weight << endl;
    }
    #endif //USE_STREAMS
    system("PAUSE");
    return EXIT_SUCCESS;
}

kyle