Passing Class object to the same class method

[infantheartlyje]

Hi folks, I have written code to random access files in c++ . I got result without creating a method for write a record to the file. I have given the code snippet below.

#include<iostream>

#include<fstream>
#include<iomanip>
using namespace std;
class student
{
 int rollno,marks;
 char name[20];
 fstream fpointer;
 
 public:
    void show();
    void get();

    
};
void student::get()
{
 cout<<"Enter the name of student:";
 cin>>name;
 cout<<"Enter the roll no. of student:";
 cin>>rollno;
 cout<<"Enter the marks of student:";
 cin>>marks;
}
int main()
{
 student record;
 fstream file;
 file.open("student.txt",ios::in|ios::out|ios::binary|ios::app);
 char flag='y';
 int i=0;
 while(flag=='y'||flag=='Y')
 {
    record.get();
    file.seekp(i*sizeof(record), ios::beg);
    file.write((char*)&record,sizeof record);
    cout<<"Enter another record(Y/N)....";
    cin>>flag;
    i++;
 }
 //file.seekg(0);
 cout<<"Roll No.\tName\tMarks"<<endl;
 file.seekp(2*sizeof(record), ios::beg);
 while(file.read((char*)&record,sizeof record))
 {
    record.show();
 }
 file.close();
 return 0;
}
void student::show()
{
 cout<<rollno<<"\t\t"<<name<<"\t"<<marks<<endl;
}

But now i created a method inside the class to write and read the record. This is time i could not write and read successfully. What is the problem here. Please tell me.

#include<iostream>

#include<fstream>
#include<iomanip>
using namespace std;
class student
{
 int rollno,marks;
 char name[20];
 
 
 public:
    void show();
    void get();
    int write(const student &,fstream &,int);
    int read(const student &,fstream &,int);
};
void student::get()
{
 cout<<"Enter the name of student:";
 cin>>name;
 cout<<"Enter the roll no. of student:";
 cin>>rollno;
 cout<<"Enter the marks of student:";
 cin>>marks;
}
int student::write(const student &s,fstream &fp,int RecNum)
{
    if( fp.seekp(RecNum*sizeof(s), ios::beg) == 0 )
        if(fp.write((char*)&s,sizeof s))
            return 1;
    return 0;
}
int student::read(const student &s,fstream &fp,int RecNum)
{
    if( fp.seekg(RecNum*sizeof(s), ios::beg) == 0 )
        if(fp.read((char*)&s,sizeof s))
            return 1;
    return 0;
}
int main()
{
 student record;
 fstream file;
 file.open("student.txt",ios::in|ios::out|ios::binary|ios::app);
 char flag='y';
 int i=0;
 
    record.get();
    record.write(record,file,2);
    
    
 

 cout<<"Roll No.\tName\tMarks"<<endl;
 
 record.read(record,file,2);

 file.close();
 return 0;
}
void student::show()
{
 cout<<rollno<<"\t\t"<<name<<"\t"<<marks<<endl;
}

[sundip]

Could you please mention what exact error you are getting ?

[infantheartlyje]

The record doesn't write into the file.

[infantheartlyje]

Could you please mention what exact error you are getting ?

The record doesn't write into the file.

[sundip]

In the method student::read line no:37. You are reading in s and not writing s value to anywhere. You are also reading first record only.

Call read method in while loop till EOF and write value of s(record) to console)cout<<)

[infantheartlyje]

In the method student::read line no:37. You are reading in s and not writing s value to anywhere. You are also reading first record only.

Call read method in while loop till EOF and write value of s(record) to console)cout<<)

You are telling me to change the read method as like below?

int student::read(const student &s,fstream &fp,int RecNum)
{
    fp.seekg(0);
	while(fp.read((char*)&s,sizeof s))
 {
	show();
 }