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Top Forums Programming Reading a whole line without betting on size Post 302363826 by broli on Wednesday 21st of October 2009 11:51:20 AM
Old 10-21-2009
Reading a whole line without betting on size

i have been googling, and came to the conclusion that there is not standard C library (or commonly used) that reads a complete line of a file, without a size parameter being involved.

so, as a little exercise i decided to think it over, and make my own

i came up with an idea, and wanted to hear comments (keeping in mind i want to learn from this)

the idea, in pseudo bable would be like this

char * readholeline ( FILE *file, size_t chunk);
   while we dont hit the end of line
      allocate a size of chunk array
      read chunk bytes into array
      add array into a new node of a linked list
   calculate how many chars we have counting all nodes
   allocate memory for all chars
   while we still have have more nodes
       copy string from node to "all chars string"
       next node  
       free previous node
    return "all chars pointer"


i discarded readin one char at a time, because it would be i/o intensive, and added the chunk parameter, because most of the time we have "some idea" of how big a file is, so we can make a "close" guess, but not quite exact ...

im still writing the real code, but wanted to know what other would think, or if someone has a better approach too

thanks Smilie

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fread(3s)																 fread(3s)

       fread, fwrite - buffered binary input/output

       #include <stdio.h>

       size_t fread(ptr, size, nitems, stream)
       void *ptr;
       size_t size, nitems;
       FILE *stream;

       size_t fwrite(ptr, size, nitems, stream)
       void *ptr;
       size_t size, nitems;
       FILE *stream;

       The  function  reads  into a block beginning at ptr, nitems of data of the size size (usually sizeof *ptr) from the named input stream.	It
       returns the number of items actually read.

       If stream is stdin and the standard output is line buffered, then any partial output line will be flushed before any call to to satisfy the

       The function appends, at most, nitems of data of the size size (usually sizeof *ptr) beginning at ptr  to  the  named  output  stream.	It
       returns the number of items actually written.

Return Values
       The and functions return 0 upon end of file or error.

See Also
       read(2), write(2), fopen(3s), getc(3s), gets(3s), printf(3s), putc(3s), puts(3s), scanf(3s)


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