Thread: setting array to 0

Hello everyone,

I'm learning about code used to open files.

I got the following code from "Sam's Teach Yourself C for Linux Programming"

I don't understand why he set filename[ ] and mode [ ] to 0.

Code:

/*demonstrating the fopen( )*/
#include <stdlib.h>
#include <stdio.h>

int main(void)
{
   FILE *fp;
   char ch, filename[40], mode[5];

   while (1)

   {
        printf("\nEnter a filename: ");
        fgets(filename, 40, stdin);
        filename[ strlen(filename) - 1] = 0;  /*sets filename[ ] to 0 ????*/
        printf("\nEnter a mode (max 3 characters): ");
        fgets(mode, 5, stdin);
        mode [ strlen(mode) - 1] = 0; /*sets mode[ ] to 0 ????*/

        /*then opens file with--- */

         if ( ( fp = fopen( filename, mode ) ) != NULL )

      /* etc. .....*/

Thanks

That has to be the fastest response I have ever had on a post.
(less than 5 minutes)
Thanks!