reading a file

This is a discussion on reading a file within the C Programming forums, part of the General Programming Boards category; my text.txt file Code: LDC 1,2 #444 LDC 1,2 #444 my program: Code: #include <stdio.h> #include <string.h> char file_array[10000]; void ...

  1. #1
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    reading a file

    my text.txt file
    Code:
    LDC 1,2 #444
    LDC 1,2 #444
    my program:
    Code:
    #include <stdio.h>
    #include <string.h>
    char file_array[10000];
    
    
    void
    readfile(char *file)
    {
      char ch;
      int i = 0;
      FILE *pfile = fopen(file, "r");
    
      if (pfile == NULL)
         {
             puts("New Files");
         }
      else
         {
             while((ch = fgetc(pfile)) != EOF)
               {
                   file_array[i] = ch;
                   i++;
               }
             file_array[i] = '\0';
             fclose (pfile);
        }
    }
    
    int main(int argc, char **argv)
         
    {
      char *filename = argv[1];
      //char test_string[50]="PRINT 1,2";
      char *sub_string;
    
      readfile(filename);
      printf("%s\n", strtok(file_array, " "));
      while ( (sub_string=strtok(NULL, ",")) != NULL)
      {
        printf("%s\n", sub_string);
      }
      return 0;
    }
    at the moment my output is

    a.out text.txt
    LDC
    1
    2 #444
    LDC 1
    2 #444

    i want to modify it so it prints out this
    LDC
    1
    2
    LDC
    1
    2

    ignoring everything after and including the #

    how do i do this?
    Last edited by 8ball; 06-06-2004 at 11:57 PM.

  2. #2
    Registered User Frobozz's Avatar
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    Give this a shot.

    Code:
    void
    readfile(char *file)
    {
      char ch;
      int i = 0;
      int comment = 0;
      FILE *pfile = fopen(file, "r");
    
      if (pfile == NULL)
    	 {
    		 puts("New Files");
    	 }
      else
    	 {
    		 while((ch = fgetc(pfile)) != EOF)
    		   {
    			   if (ch == '#')
    			   {
    				 comment = 1;
    			   }
    			   else if (ch == '\n')
    			   {
    				 comment = 0;
    			   }
     
    			   if (comment == 0)
    			   {
    				  file_array[i] = ch;
    				  i++;
    			   }
    		   }
    		 file_array[i] = '\0';
    		 fclose (pfile);
    	}
    }

  3. #3
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    when my input is
    LDC 1,2 #444
    LDC 1,2 # dkljdlkdj
    Print -4 #dldkdl;

    its giving me this output
    LDC
    1
    2
    LDC 1
    2
    Print -4

    but i want it to be like this
    LDC
    1
    2
    LDC
    1
    2
    Print
    -4

  4. #4
    and the hat of int overfl Salem's Avatar
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    Well first you need to read the file a line at a time, rather than reading the whole file into an array

    Here are the first couple of steps
    Code:
    char buff[BUFSIZ];
    while ( fgets( buff, BUFSIZ, pfile ) != NULL ) { /* read each line */
        char *hash = strchr( buff, '#' );  /* is there a comment? */
        if ( hash != NULL ) *hash = '\0'; /* line is now commentless */
        /* now do your strtok'ing */
    }
    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.

  5. #5
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    will i need linked lists?

  6. #6
    Registered User pinko_liberal's Avatar
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    Quote Originally Posted by 8ball
    my text.txt file
    Code:
    LDC 1,2 #444
    LDC 1,2 #444
    my program:
    Code:
      char ch;
    
             while((ch = fgetc(pfile)) != EOF)
    Your code original code worked?
    The one who says it cannot be done should never interrupt the one who is doing it.

  7. #7
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    nope...

  8. #8
    Registered User pinko_liberal's Avatar
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    Quote Originally Posted by 8ball
    nope...
    fgetc() returns an int, EOF is usually an int value that cannot be represented as a char, so you might end up with an infinite loop unless you declare ch as a int.
    The one who says it cannot be done should never interrupt the one who is doing it.

  9. #9
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    Quote Originally Posted by Salem
    Well first you need to read the file a line at a time, rather than reading the whole file into an array

    Here are the first couple of steps
    Code:
    char buff[BUFSIZ];
    while ( fgets( buff, BUFSIZ, pfile ) != NULL ) { /* read each line */
        char *hash = strchr( buff, '#' );  /* is there a comment? */
        if ( hash != NULL ) *hash = '\0'; /* line is now commentless */
        /* now do your strtok'ing */
    }
    where do i place this?

  10. #10
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    this is what my code looks like now
    Code:
    #include <stdio.h>
    #include <string.h>
    char file_array[10000];
    
    
    /*void
    readfile(char *file)
    {
      char ch;
      int i = 0;
      FILE *pfile = fopen(file, "r");
    
      if (pfile == NULL)
         {
             puts("New Files");
         }
      else
         {
             while((ch = fgetc(pfile)) != EOF)
               {
    	   	if (ch==35)
    			break;
    			else
    			{
                   file_array[i] = ch;
                   i++;
    	       }
               }
             file_array[i] = '\0';
             fclose (pfile);
        }
    }
    */
    void
    readfile(char *file)
    {
      int ch;
      int i = 0;
      int comment = 0;
      FILE *pfile = fopen(file, "r");
    
      if (pfile == NULL)
    	 {
    		 puts("New Files");
    	 }
      else
    	 {
    		 while((ch = fgetc(pfile)) != EOF)
    		   {
    			   if (ch == '#')
    			   {
    				 comment = 1;
    			   }
    			   else if (ch == '\n')
    			   {
    				 comment = 0;
    			   }
     
    			   if (comment == 0)
    			   {
    				  file_array[i] = ch;
    				  i++;
    			   }
    		   }
    		 file_array[i] = '\0';
    		 fclose (pfile);
    	}
    }
    
    void breakup(char *file_array)
    {
      
    
      	//char test_string[50]="PRINT 1,2";
      	char *sub_string;
    	printf("%s\n", strtok(file_array, " "));
      	while ( (sub_string=strtok(NULL, ",")) != NULL)
      	{
        		printf("%s\n", sub_string);
      	}
    }
    
    int main(int argc, char **argv)
    {
    char *filename = argv[1];
      	readfile(filename);
      	breakup(file_array);
      	return 0;
    }
    and my output now is
    LDC
    1
    2
    LDC 1
    2
    Print -4

  11. #11
    and the hat of int overfl Salem's Avatar
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    > where do i place this?
    OK, the whole thing
    Code:
    int main ( int argc, char **argv ) {
        char buff[BUFSIZ];
        FILE *pfile = fopen(argv[1], "r");
        while ( fgets( buff, BUFSIZ, pfile ) != NULL ) { /* read each line */
            char *sub_string;
            char *hash = strchr( buff, '#' );  /* is there a comment? */
            if ( hash != NULL ) *hash = '\0'; /* line is now commentless */
            /* now do your strtok'ing */
            printf("%s\n", strtok(buff, " "));
            while ( (sub_string=strtok(NULL, ",\n")) != NULL)
            {
                    printf("%s\n", sub_string);
            }
        }
        return 0;
    }
    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.

  12. #12
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    thanks alot for that

    what would be the parameter if i want to place all that in a function?

  13. #13
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    Code:
    void breakup()
    {
    char buff[BUFSIZ];
        
        while ( fgets( buff, BUFSIZ, pfile ) != NULL ) { /* read each line */
            char *sub_string;
            char *hash = strchr( buff, '#' );  /* is there a comment? */
            if ( hash != NULL ) *hash = '\0'; /* line is now commentless */
            /* now do your strtok'ing */
            printf("%s\n", strtok(buff, " "));
            while ( (sub_string=strtok(NULL, ",\n")) != NULL)
            {
                    printf("%s\n", sub_string);
            }
        }
    }
    
    int main ( int argc, char **argv ) {
      FILE *fp = fopen(argv[1], "r");
      breakup(fp);
    
      return 0;
    }
    is this the way to do it?

  14. #14
    and the hat of int overfl Salem's Avatar
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    > is this the way to do it?
    If you fix breakup() to accept a parameter, yes
    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.

  15. #15
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    void breakup(char *pfile)
    ?

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