Sams Teach Yourself C in 21 Days

Listing 16.7 demonstrates the use of feof(). When you’re prompted for a filename, enter

the name of any text file—one of your C source files, for example, or a header file such

as stdio.h. Just be sure that the file is in the current directory, or else enter a path as part

of the filename. The program reads the file one line at a time, displaying each line on

stdout, untilfeof()detects end-of-file.

LISTING16.7 feof.c. Using feof()to detect the end of a file

1: /* Detecting end-of-file. */

2: #include <stdlib.h>

3: #include <stdio.h>

4:

5: #define BUFSIZE 100

6:

7: int main( void )

8: {

9: char buf[BUFSIZE];

10: char filename[60];

11: FILE *fp;

12:

13: puts(“Enter name of text file to display: “);

14: gets(filename);

15:

16: /* Open the file for reading. */

17: if ( (fp = fopen(filename, “r”)) == NULL)

18: {

19: fprintf(stderr, “Error opening file.”);

20: exit(1);

21: }

22:

23: /* If end of file not reached, read a line and display it. */

24:

25: while ( !feof(fp) )

26: {

27: fgets(buf, BUFSIZE, fp);

28: printf(“%s”,buf);

29: }

30:

31: fclose(fp);

32: return 0;

33: }

Enter name of text file to display:

hello.c

#include <stdio.h>

int main( void )

{

printf(“Hello, world.”);

return(0);

}

464 Day 16

INPUT

INPUT/

OUTPUT

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