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fprintf

The fprintf ("file print formatted") command is identical to printf, except that its first parameter is a stream to which to send output. The following code example is the same as the one for printf, except that it sends its output to the text file snazzyjazz.txt.

#include <stdio.h>
#include <errno.h>

int main()
{
  int my_integer = -42;
  unsigned int my_ui = 23;
  float my_float = 3.56;
  double my_double = 424242.171717;
  char my_char = 'w';
  char my_string[] = "Pardon me, may I borrow your nose?";

  FILE *my_stream;
  char my_filename[] = "snazzyjazz.txt";
  my_stream = fopen (my_filename, "w");

  fprintf (my_stream, "Integer: %d\n", my_integer);
  fprintf (my_stream, "Unsigned integer: %u\n", my_ui);

  fprintf (my_stream, "The same, as hexadecimal: %#x %#x\n", my_integer, my_ui);

  fprintf (my_stream, "Floating-point: %f\n", my_float);
  fprintf (my_stream, "Double, exponential notation: %17.11e\n", my_double);

  fprintf (my_stream, "Single character: %c\n", my_char);
  fprintf (my_stream, "String: %s\n", my_string);

  errno = EACCES;
  fprintf (my_stream, "errno string (EACCES): %m\n");

  /* Close stream; skip error-checking for brevity of example */
  fclose (my_stream);

  return 0;
}