Thread: what is "b:" ??? (input/output)

i'm following a textbook to learn C, and the following example was used to show how to Program-Controlled Input and Output files...

Code:

#include <stdio.h>
#define KMS_PER_MILE 1.609
 
int
main(void)
 
{
 
double miles, kms;
 
/* set pointers */
FILE *inp, *outp;
 
/* open input/output files */
inp = fopen("b:input_file.txt", "r"); 
outp = fopen("b:output_file.txt", "w");
 
/* get and echo info */
fscanf(inp, "%1f", miles);
fprintf(outp, "The distance in miles is %.2f.\n", miles);
 
/* convert distance to kms */
kms = KMS_PER_MILE * miles;
 
/* display distance in kms */
fprintf(outp, "That equals %.2f kilometers.\n", kms);
 
/* close files */
fclose(inp);
fclose(outp);
 
return(0);
 
}

the trouble is, I run it and it doesn't work.

I have tried searching for "b:" as it was used here:

Code:

/* open input/output files */
inp = fopen("b:input_file.txt", "r"); 
outp = fopen("b:output_file.txt", "w");

in google to find out what it does, but I have found nothing.


What the heck?