The simple answer is:
while(fscanf(pFile, " %59[^\n]%*c", x) == 1)
Here %[^\n]
uses the character class [stuff]
to read everything up to the newline. %*c
simply reads and discards the newline without adding it to the match count for fscanf
.
However for line-oriented input, you should really use one of the line-oriented functions provided by the standard library (e.g. fgets
or POSIX getline
).
Using fgets & strtok
As you have taken from the comment, the use of feof
is going to cause you nothing but grief. You will want to simply use the return of fgets
to determine end of file. Here is an example that puts all the pieces of the puzzle together:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAXWDS 20
#define MAXCHR 60
int main (int argc, char **argv) {
char line[MAXCHR] = {0};
char *words[MAXWDS] = {NULL};
FILE *pFile = NULL;
size_t i, index = 0;
/* open file for reading (if provided), or read from stdin */
if (!(pFile = argc > 1 ? fopen (argv[1], "r") : stdin)) {
fprintf (stderr, "error: file open failed '%s'.\n", argv[1]);
return 1;
}
while (fgets (line, 60, pFile))
{
char *p = line;
/* split line into tokens, stored in words[] */
for (p = strtok (p, " \r\n"); p; p = strtok (NULL, " \r\n")) {
words[index++] = strdup (p); /* allocate & copy */
if (index == MAXWDS) /* check pointer limit */
break;
}
}
if (pFile != stdin) fclose (pFile);
/* output in a single line */
for (i = 0; i < index; i++) {
printf (" %s", words[i]);
free (words[i]); /* free allocated memory */
}
putchar ('\n');
return 0;
}
Compile
gcc -Wall -Wextra -o bin/fgets_strtok fgets_strtok.c
Output
$ ./bin/fgets_strtok dat/hellomark.txt
Hello my name is mark. and im going to love c!
Note: to simply print the line out with spaces between the words, as long as there is already a space between each of the words in each line, there is no reason to go to the trouble to separate each line into individual words, you can simply print the contents of each line out in a space separate fashion. The only issue you run into using fgets
is that it will also read the newline
(or carriage return, newline
) as part of the string. That is simple to remove. You can replace the entire read loop with:
while (fgets (line, 60, pFile))
{
size_t len = strlen (line);
/* strip trailing newline (or carriage return newline ) */
while (len && (line[len-1] == '\n' || line[len-1] == '\r'))
line[--len] = 0; /* overwrite with null-terminating char */
words[index++] = strdup (line); /* allocate & copy */
if (index == MAXWDS) /* check pointer limit */
break;
}
Output
$ ./bin/fgets_mark <dat/hellomark.txt
Hello my name is mark. and im going to love c!
Standard Way to Read from File Only (not File or stdin)
I apologize for the getting ahead of you a bit by including a way to either open a file (if provided on the command line) or read from stdin
(if no filename was provided). The standard way is to first check that the correct number of arguments were provided on the command line, and then open the filename provided, validate it is open, and then process input. What I did was throw a ternary operator
into the fopen
command that said.
pFile = argc > 1 ? fopen (argv[1], "r") : stdin
The right side of the '='
sign is a ternary operator, which is simply a shorthand for if -> then -> else
. What it does is ask is argc > 1
? If that tests true
, then pFile = fopen (argv[1], "r");
. If argc > 1
tests false
, then pFile = stdin;
See if the standard way makes more sense:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAXWDS 20
#define MAXCHR 60
int main (int argc, char **argv) {
char line[MAXCHR] = {0};
char *words[MAXWDS] = {NULL};
FILE *pFile = NULL;
size_t i, index = 0;
/* validate sufficient input */
if (argc < 2 ) {
fprintf (stderr, "error: insufficient input, usage: %s filename\n", argv[0]);
return 1;
}
/* open file provided on command line for reading */
pFile = fopen (argv[1], "r");
if (!pFile) {
fprintf (stderr, "error: file open failed '%s'.\n", argv[1]);
return 1;
}
while (fgets (line, 60, pFile)) /* read each line in file */
{
size_t len = strlen (line);
/* strip trailing newline (or carriage return newline ) */
while (len && (line[len-1] == '\n' || line[len-1] == '\r'))
line[--len] = 0; /* overwrite with null-terminating char */
words[index++] = strdup (line); /* allocate & copy */
if (index == MAXWDS) /* check pointer limit */
break;
}
if (pFile != stdin) fclose (pFile);
/* output in a single line */
for (i = 0; i < index; i++) {
printf (" %s", words[i]);
free (words[i]); /* free allocated memory */
}
putchar ('\n');
return 0;
}