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Please correct the error in my program. When i run the program on turbo c++ 3, it out

Discussion in 'C++' started by tharun518, Feb 25, 2009.

  1. tharun518

    tharun518 New Member

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    Please correct the error in my program. When i run the program on turbo c++ 3, it output 3 times. Also When i enter more than 1 entry only the last entry is outputted. Also it is outputted 3 times.
    Code:
    #include<fstream.h>
    #include<iostream.h>
    #include<conio.h>
    class  student
    {
    int rollno;
    char name[20];
    int tm;
    public:
    void  input();
    void transfer();
    void output();
    }
    obj;
    void  student::input()
    {
    char ch='y';
    ofstream  outf;
    outf.open("mark.dat");
    while(ch=='y')
    {
    cout<<"Enter  rollno, name and  mark";
    cin>>rollno>>name>>tm;
    outf.write((char*)&obj,sizeof(obj));
    cout<<"Wish  to enter more(Y/N)?\n";
    cin>>ch;
    }
    outf.close();
    }
    void  student::transfer()
    {
    ofstream outf;
    ifstream  inf;
    inf.open("mark.dat");
    outf.open("trans.dat");
    while(inf)
    {
    inf.read((char*)&obj,sizeof(obj));
    outf.write((char*)&obj,sizeof(obj));
    }
    outf.close();
    inf.close();
    }
    void  student:utput()
    {
    ifstream  inf;
    inf.open("trans.dat");
    while(inf)
    {
    inf.read((char*)&obj,sizeof(obj));
    cout<<"\nRollno  "<<rollno;
    cout<<"\nName "<<name;
    cout<<"\nTotal  "<<tm;
    }
    inf.close();
    }
    void  main()
    {
    clrscr();
    student  obj;
    obj.input();
    obj.transfer();
    obj.output();
    getch();
    }
     
    Last edited by a moderator: Feb 25, 2009
  2. xpi0t0s

    xpi0t0s Mentor

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    Re: Please correct the error in my program. When i run the program on turbo c++ 3, it

    Please indent your code. It's very difficult to follow if there's no indentation.
     
  3. tharun518

    tharun518 New Member

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    Re: Please correct the error in my program. When i run the program on turbo c++ 3, it

    I don't know to indent. Please correct the error. The progaram is to copy content of a file to another file.
     
  4. xpi0t0s

    xpi0t0s Mentor

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    Re: Please correct the error in my program. When i run the program on turbo c++ 3, it

    Here's some non-indented code:
    Code:
    int main()
    {
    printf("Hello\n");
    return 0;
    }
    
    And here's some indented code (I used spaces):
    Code:
    int main()
    {
        printf("Hello\n");
        return 0;
    }
    
    When you have multiple nested code blocks, indentation makes the code a lot more readable.
     
  5. tharun518

    tharun518 New Member

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    Re: Please correct the error in my program. When i run the program on turbo c++ 3, it

    I have tried to intend it.

    Thank you very much for taking time. I am from India and here we learn about only basics of c++ and our syllabus is based on turbo c++ 3. So i use turbo c++ and i don't know much about c++ programing. So i cannot implement instructions you give on modern c++.

    I tried new changes. But i still have some little problems. The program is to transfer content of one file to another. When i input only one entry, the program works. But when more than one entry is used it out puts only 1 or 2. Kindly please correct the problem.

    Here is the new code by correcting the previous errors.


    Code:
     
    #include<fstream.h>
    #include<iostream.h>
    #include<conio.h>
    class student
    {
           int rollno;
           char name[20];
           int tm;
           public:
           void input();
           void transfer();
           void output();
     };
    void student::input()
    {
           char ch='y';
           ofstream outf;
           outf.open("mark.dat");
           while(ch=='y')
          {
                   cout<<"Enter rollno, name and mark\n";
                   cin>>rollno>>name>>tm;
                   outf.write((char*)this,sizeof(student));
                   cout<<"Wish to enter more(Y/N)?\n";
                   cin>>ch;
          }
         outf.close();
    }
    void student::transfer()
    {
        ofstream outf;
        ifstream inf;
        inf.open("mark.dat");
        outf.open("trans.dat");
        while( inf.read(( char* )this,sizeof(student))) 
       {
              outf.write(( char* )this,sizeof( student ) );
       }
       outf.close();
       inf.close();
    }
    void student::output()
    {
       ifstream inf;
       inf.open("trans.dat");
       while (inf.read((char*)this, sizeof(student)))
       {
            inf.read(( char* )this,sizeof( student ) );
            cout<<"\nRollno "<<rollno;
            cout<<"\tName "<<name;
            cout<<"\tTotal "<<tm<<'\n';
       }
       inf.close();
    }
    void main()
    {
        clrscr();
        student obj;
        obj.input();
        obj.transfer();
        obj.output();
        getch();
     }
    
     
  6. xpi0t0s

    xpi0t0s Mentor

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    Re: Please correct the error in my program. When i run the program on turbo c++ 3, it

    Don't PM me to demand answers please.

    What input do you give, and what output do you get? Enter say 3 or 4 records and use copy and paste to paste the resulting screen exactly - showing both data entered and results. Paste into a code block to maintain formatting.

    I am a little concerned by "inf.read(( char* )this,sizeof(student))" and the write equivalent. If these functions are designed for text then the data should be converted to text, not just cast to char*. Apart from this the code seems to be OK so the input and output should help me see what's going wrong.
     
  7. tharun518

    tharun518 New Member

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    Re: Please correct the error in my program. When i run the program on turbo c++ 3, it

    At last my program to transfer content of one file to another. Here is the full program for further reference to other users.
    Code:
    #include<fstream.h>
    #include<iostream.h>
    #include<conio.h>
    class student
    {
    int rollno;
    char name[20];
    int tm;
    public:
    	void input();
    	void transfer();
    	void output();
    	};
    void student::input()
    {
    char ch='y';
    ofstream outf;
    outf.open("mark.dat");
    while(ch=='y')
    {
    cout<<"Enter rollno, name and mark\n";
    cin>>rollno>>name>>tm;
    outf.write((char*)this,sizeof(student));
    cout<<"Wish to enter more(Y/N)?\n";
    cin>>ch;
    }
    outf.close();
    }
    void student::transfer()
    {
    ofstream outf;
    ifstream inf;
    inf.open("mark.dat");
    outf.open("trans.dat");
    while( inf.read(( char* )this,sizeof(student))) 
    {
    outf.write(( char* )this,sizeof( student ) );
    }
    outf.close();
    inf.close();
    }
    void student::output()
    {
    ifstream inf;
    inf.open("trans.dat");
    while (inf.read((char*)this, sizeof(student)))
    {
    cout<<"\nRollno "<<rollno;
    cout<<"\tName "<<name;
    cout<<"\tTotal "<<tm<<'\n';
    }
    inf.close();
    }
    void main()
    {
    clrscr();
    student obj;
    obj.input();
    obj.transfer();
    obj.output();
    getch();
    }
    
     
    shabbir likes this.
  8. shabbir

    shabbir Administrator Staff Member

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    Re: Please correct the error in my program. When i run the program on turbo c++ 3, it

    I really like this approach and some repu your way
     
  9. tharun518

    tharun518 New Member

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    Re: Please correct the error in my program. When i run the program on turbo c++ 3, it

    Thank you very much admin. I also had a forum like this. But now its down. I am after the exams.
     
  10. shabbir

    shabbir Administrator Staff Member

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    Re: Please correct the error in my program. When i run the program on turbo c++ 3, it

    PM me the url if you want to.
     
  11. xpi0t0s

    xpi0t0s Mentor

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    Re: Please correct the error in my program. When i run the program on turbo c++ 3, it

    *slaps forehead* Yes, that would cause the problem:
    Code:
    while (inf.read((char*)this, sizeof(student)))
       {
            inf.read(( char* )this,sizeof( student ) );
    
    Easy mistake to make!
     

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