problem with text files

This is a discussion on problem with text files within the C++ Programming forums, part of the General Programming Boards category; hi.. i'm learning C++ and i have a problem that has never happened to me before: i have a project ...

  1. #1
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    problem with text files

    hi..
    i'm learning C++ and i have a problem that has never happened to me before:

    i have a project where i use text files.. i open the file, close it, start a FOR, open the file again (inside the FOR), and when i close the file again (inside the FOR) an error apears saying "..The memory could not be "read"".

    the weirdest thing is that when i run the program in Debug, this doesn't happen and the program does what i want!!!

    Code:
    int count;
    FILE *fin;
    char wordtxtfile[50];
    char txtfile[2][10];
    /*****************************/
    strcpy(txtfile[0],"PT.txt");
    strcpy(txtfile[1],"FR.txt");
    /*****************************/
    
    count=11;
    for (int x=0;x<2;x++)
     {
      if ((fin=fopen(txtfile[x],"r"))==NULL)
        printf ("\nError");
      else
       {
         fclose(fin);
         for (int y=0;y<=count;y++)
          {
            fin=fopen(txtfile[x],"r");
            while ((fscanf(fin,"%s",wordtxtfile))!=EOF)
             {
               printf ("%s\n",wordtxtfile);
             }
            fclose(fin);
          }
       }
    }
    Please help me! i need this problem solved quickly.. =S

    edit: i misplaced the fclose(fin)
    Last edited by Gather; 06-04-2006 at 07:10 PM.

  2. #2
    Registered User subdene's Avatar
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    I have no idea why you are trying to do here, your code seems a bit nackered to me.

    If the file opens successfully, then you go and open it up again within the else..... why is?

    Then when you are in the for loop, you open the file and then close it 11 times....

    I dont get this program in the slightest.
    Be a leader and not a follower.

  3. #3
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    Quote Originally Posted by subdene
    I have no idea why you are trying to do here, your code seems a bit nackered to me.

    If the file opens successfully, then you go and open it up again within the else..... why is?

    Then when you are in the for loop, you open the file and then close it 11 times....

    I dont get this program in the slightest.
    sry.. i didnt explain what the program does.. and i only put the important part of the program!!
    basically, it opens each file (PT.txt and FR.txt) ,the first time, to see if it exists.. then closes it and starts the for.. to print the words from the file 11 times!!

  4. #4
    Registered User whiteflags's Avatar
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    Stop opening and closing the file over and over again. fopen returns a NULL if it fails. That's all that you need to check.

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    Quote Originally Posted by citizen
    Stop opening and closing the file over and over again. fopen returns a NULL if it fails. That's all that you need to check.
    there's a reason why i'm doing that.. but i'm not going to explain it now..
    the question is.. does the problem come from there?!?!

  6. #6
    Registered User whiteflags's Avatar
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    Yes. The file's not open when you try to use fscanf in the while loop.

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    Code:
    fin=fopen(txtfile[x],"r");
    while ((fscanf(fin,"%s",wordtxtfile))!=EOF)
    it's not opened??

  8. #8
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    Well, you do not do any error checking, so you really can't be sure.

    And do please note that this is the C++ forum.
    Code:
    #include <stdio.h>
    
    void J(char*a){int f,i=0,c='1';for(;a[i]!='0';++i)if(i==81){
    puts(a);return;}for(;c<='9';++c){for(f=0;f<9;++f)if(a[i-i%27+i%9
    /3*3+f/3*9+f%3]==c||a[i%9+f*9]==c||a[i-i%9+f]==c)goto e;a[i]=c;J(a);a[i]
    ='0';e:;}}int main(int c,char**v){int t=0;if(c>1){for(;v[1][
    t];++t);if(t==81){J(v[1]);return 0;}}puts("sudoku [0-9]{81}");return 1;}

  9. #9
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    Quote Originally Posted by jafet
    Well, you do not do any error checking, so you really can't be sure.

    And do please note that this is the C++ forum.
    what do you mean?.. i did the error checking in the begining

  10. #10
    Registered User whiteflags's Avatar
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    In your code segment I do not see how it is necessary to open and close the file with every iteration of the loop, it doesn't make sense and it's slow, and you don't do the error checking for each iteration.

    Have you considered opening the file once, reading it once, and printing the contents 11 times, as you intended? It's a lot less likely to die that way.

  11. #11
    ZuK
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    Quote Originally Posted by Gather
    the first time, to see if it exists.. then closes it and starts the for.. to print the words from the file 11 times!!
    Your code tries to open and close each file 13 times and would prints its contents 12 times
    Kurt

  12. #12
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    Quote Originally Posted by citizen
    In your code segment I do not see how it is necessary to open and close the file with every iteration of the loop, it doesn't make sense and it's slow, and you don't do the error checking for each iteration.

    Have you considered opening the file once, reading it once, and printing the contents 11 times, as you intended? It's a lot less likely to die that way.
    How do i print the contents 11 times without reopening the file? so that it goes to the begining of the file at the start of every loop.

  13. #13
    (?<!re)tired Mario F.'s Avatar
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    store the contents to a string and then close the file. Use the string to print the contents.
    The programmer’s wife tells him: “Run to the store and pick up a loaf of bread. If they have eggs, get a dozen.”
    The programmer comes home with 12 loaves of bread.


    Originally Posted by brewbuck:
    Reimplementing a large system in another language to get a 25% performance boost is nonsense. It would be cheaper to just get a computer which is 25% faster.

  14. #14
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    I cant.. =S I have to use the files.. cant use strings

  15. #15
    C++ Witch laserlight's Avatar
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    I have to use the files.. cant use strings
    Why not?
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