If you want to write a single character to a stream other than
stdout, you can use the putc function. This function is
very similar to putchar, but accepts an argument that specifies
the stream to which to write. It takes a single integer parameter containing
a character (the argument can be a single-quoted text character, as in the
example below), and sends the character to the specified stream. If a write error
occurs, putc returns EOF; otherwise, it returns the integer
it was passed. This can simply be disregarded, as in the example below.
The following code example creates a text file called
snazzyjazz.txt. It then writes an X, a space, and then a
line of ten exclamation marks (!!!!!!!!!!) to the file, and a
newline character to it using the putc function. Notice the use
of the for loop; by this means, putchar can be used not
just for one character, but multiple times. , then writes ten
exclamation mark characters (!!!!!!!!!!)
#include <stdio.h>
int main()
{
int i;
FILE *my_stream;
char my_filename[] = "snazzyjazz.txt";
my_stream = fopen (my_filename, "w");
putc ('X', my_stream);
putc (' ', my_stream);
for (i=1; i<=10; i++)
{
putc ('!', my_stream);
}
putc ('\n', my_stream);
/* Close stream; skip error-checking for brevity of example */
fclose (my_stream);
return 0;
}
There is another function in the GNU C Library called fputc. It
is identical to putc in most respects, except that putc is
usually implemented as a macro function and is highly optimised, so is
preferable in most situations.
