Thread: file handling open function error

Hey there,

I have an error in file handling. When i use open function with ios::binary mode, it says-

no matching function for call to `std::basic_fstream<char, std::char_traits<char> >:pen(const char[8], bool)'

here are the codes. 2 files, one for entering data into file, one for deleting records.

the following is for writing records to file

Code:

#include<iostream.h>#include<fstream.h>


class employee
{
      int code;
      char name[20];
      char desig[15];
      float salary;
      
      public: void get_emp();
};


void employee:: get_emp()
{
     cout<<"Code--> ";
     fflush(stdin);
     cin>>code;
     cout<<"Name--> ";
     fflush(stdin);
     gets(name);
     cout<<"Designation--> ";
     fflush(stdin);
     gets(desig);
     cout<<"Salary--> ";
     fflush(stdin);
     cin>>salary;
}


int main()
{
    fstream f;
    char ch;
    f.open("EMP.dat", ios::binary||ios::app);
    employee emp;
    cout<<"Enter data:\n";
    do
    {
                 emp.get_emp();
                 f.write((char*)&emp,sizeof(emp));
                 cout<<"Entre more???(y/n)";
                 cin>>ch;
    }while((ch=='y')||(ch=='Y'));
    f.close();
    system("pause>null");
    return 0;
}

the following is for deleting records

Code:

#include<iostream.h>#include<fstream.h>
#include<stdlib.h>
struct employee
{
       int code;
       char name[20];
       char desig[15];
       float salary;
}emp;


int main()
{
    int xcode; //temporary declaration for employee code
    int flag = 0;
    fstream ef, tf; 
    //ef opened for reading, tf opened for transferring all records including modified record 
    ef.open("EMP.dat", ios::binary|| ios::in);
    tf.open("TEMP.dat", ios::binary|| ios::out);
    cout<<"Enter employee code to delete:";
    cin>>xcode;
    while(ef)
    {
             if(!ef)
                exit(0);
             ef.read((char*)&emp, sizeof(emp));
             if(emp.code == xcode)
             {
                            flag = 1;
             }
             else
                tf.write((char*)&emp, sizeof(emp));
    }
    ef.close();
    tf.close();
    if(flag == 1)
       cout<<"Record deleted.";
    else
       cout<<"Not found.";
    fstream xf, yf;
    //tf opened for reading
    xf.open("TEMP.dat", ios::binary||ios::in);
    //ef opened for copying all records from TEMP.dat
    yf.open("EMP.dat",ios::binary||ios::out);
    while(xf)
    {
             if(!xf)
                exit(0);
             xf.read((char*)&emp, sizeof(emp));
             yf.write((char*)&emp, sizeof(emp));
    }
    xf.close();
    yf.close();
    system("pause");
    return 0;
}

Please help,

thank you

Hi! You may remember me from Stack Overflow but the answer is still: logical or is two pipes, but this isn't a logical or, but a bitwise or, which is just a single pipe. You can see an example of such single pipes here: std::basic_filebuf:pen - cppreference.com

i found the error, you were correct, sorry. | is what is to be put, not ||. But there is one more problem. the program is working, but after i enter the records with the 1st code, and then i execute the 2nd code for deletion, and enter a record i want to delete(I have entered that record earlier), it says not found. Also, i go to my folder and open the EMP file to find it empty.

You've got a lot of ancient-style headers (like fstream.h instead of fstream etc). Anyway, your write program isn't writing a file for me (well, it is, but it's all zeroes). Changing it to "ofstream f;" works, depressingly.

I don't know about the ancient part, but this is in my syllabus and i must follow it. Changing it to ofstream makes no difference bro.

Originally Posted by Arjun Bhat

I don't know about the ancient part, but this is in my syllabus and i must follow it. Changing it to ofstream makes no difference bro.

Did you change the logical ORs (||) to bitwise ORs (|) ?

Oh, and don't call me bro.

Originally Posted by Arjun Bhat

I don't know about the ancient part, but this is in my syllabus and i must follow it. Changing it to ofstream makes no difference bro.

I don't have the pre-(standard)C++ fstream.h and iostream.h etc headers, so I don't know if things worked differently back then; they probably did, but I don't know what the differences are.