Unable to open a file for reading

This is a discussion on Unable to open a file for reading within the C Programming forums, part of the General Programming Boards category; Hi I am a beginer to C Programming.I was trying to open a .txt file for reading but couldnt do ...

  1. #1
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    Question Unable to open a file for reading

    Hi
    I am a beginer to C Programming.I was trying to open a .txt file for reading but couldnt do that this is my code..Help me out.

    Code:
    #include<stdio.h>
    #include<conio.h>
    main()
    {
    FILE *fp;
    clrscr();
    fp=fopen("raghu.txt","r");
    if(fp==NULL)
    printf("ERROR IN OPENING THE FILE");
    else
    {
    printf("hi");
    fprintf(fp,"\n HI");
    }
    fgetc(fp);
    fclose(fp);
    getch();
    }

  2. #2
    Deathray Engineer MacGyver's Avatar
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    1. You didn't ask a question.
    2. You're checking if fp is NULL, but if it is, you use it anyway.
    3. You are trying to write and read on a file you're opening for reading.
    4. You're using non-standard code.


    So your question is?

  3. #3
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    I did not get the 4 point.."You're using non-standard code." can you tell me more about that ,Mac

  4. #4
    CSharpener vart's Avatar
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    you should write
    int main()
    explicitely

    and not ignore the return value of fgetc
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  5. #5
    CSharpener vart's Avatar
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    Quote Originally Posted by raghuveerd View Post
    I did not get the 4 point.."You're using non-standard code." can you tell me more about that ,Mac
    conio.h is not a standard header
    all function declared in it - are not standard

    using them - makes code not portable - You cannot compile your code on differrent compiler / OS.


    You should avoid posting such code - it makes hard to compile it by the people you ask for help... Not many people will take your code, remove non-portable parts just to compile and see what is the problem...

    You can avoid such code in your application at all (better) or just remove it before posting a sniplet of the code to the board
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  6. #6
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    i made some changes ..but still cant read anything
    Code:
    #include<stdio.h>
    #include<conio.h>
    int main()
    {
    FILE *fp;
    clrscr();
    fp=fopen("raghu.txt","r");
    if(fp==NULL)
    printf("ERROR IN OPENING THE FILE");
    else
    {
    printf("hi");
    fprintf(fp,"\n HI");
    }
    
    fclose(fp);
    getch();
    }

  7. #7
    CSharpener vart's Avatar
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    you still opening for reading - and trying to write
    don't close file if you failed to open it - close only if openign was successful
    indent your code properly
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  8. #8
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    I am sorry but i have a questions..Is this forum not intended for beginers in C Programming. I want to know if i am really posting silly questions wasting time of experienced programmers.

  9. #9
    Deathray Engineer MacGyver's Avatar
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    Quote Originally Posted by raghuveerd View Post
    I am sorry but i have a questions..Is this forum not intended for beginers in C Programming. I want to know if i am really posting silly questions wasting time of experienced programmers.
    Of course it's a place for new C programmers to ask questions.

    The problem, however, is that you didn't ask a question. You dumped code here with a blanket "doesn't work" message. Of course it doesn't work. If it worked, you wouldn't be asking for help. It's irritating to try to help solve a problem with no information on said problem.

    As far as your code goes, you're still opening a file for reading, but you're trying to write to it. You've been alerted about this like twice before. This will not work, and could result in very weird behavior.

  10. #10
    and the hat of wrongness Salem's Avatar
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    > fp=fopen("raghu.txt","r");
    This is for reading from a file.

    > fprintf(fp,"\n HI");
    This is for writing to a file.

    Basically, decide what you want to do, then edit the code accordingly.

    For example, fgets() and fscanf() are file reading functions.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  11. #11
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    The thing i want to do is to print the text in raghu.txt on the screen. Can i do that!

  12. #12
    Deathray Engineer MacGyver's Avatar
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    Yes, you can. Use fgets().

  13. #13
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    read it in with the functions Salem wrote, then printf it out.

  14. #14
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    Thanks a lot..i got it now..actually i was confused with the what fprintf and fscanf does...
    thanka a lot Mac,Salem,Rob,vart

  15. #15
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    Now i can print the text in my file on to the screen..is the right way to do it

    Code:
    #include<stdio.h>
    
    int main()
    {
    FILE *fp;
    char *str;
    clrscr();
    fp=fopen("raghu.txt","r");
    if(fp==NULL)
        printf("ERROR IN OPENING THE FILE");
    else
        {
         printf("hi,this is the text in your file\n");
         fgets(str,20,fp);
         }
    printf("&#37;s",str);
    fclose(fp);
    
    getch();
    }

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