Thread: I hope it's usefull.

Looks good, but a couple tips..:

- Indent/returns. No one likes reading one huge strip of code, even if it wasn't your fault.

- Instead of having a huge lookup table for all of the values, it's easier to pick a random number between 30 ('0') and 122 ('z'), and use that to fill your file. For reference on the numbers that correspond to letters: Ascii Table - ASCII character codes and html, octal, hex and decimal chart conversion

- Make the file-size customizable on all of its dimensions. #defines or interpreting command-line arguments are the best ways to do this.

Originally Posted by memcpy

Looks good, but a couple tips..: - Indent/returns. No one likes reading one huge strip of code, even if it wasn't your fault. - Instead of having a huge lookup table for all of the values, it's easier to pick a random number between 30 ('0') and 122 ('z'), and use that to fill your file. For reference on the numbers that correspond to letters: Ascii Table - ASCII character codes and html, octal, hex and decimal chart conversion - Make the file-size customizable on all of its dimensions. #defines or interpreting command-line arguments are the best ways to do this.

The only one i understand is the first one and i fixed that.

Originally Posted by TheBigH

You're generating every eight-character sequence from a 95 symbol character set. There will be 95^8 such sequences, each nine characters long (sequence plus newline). Each character is one byte. So the file size will be 9*(95^8)=59,707,838,816,015,625 bytes. That's something like six million gig. Don't do it.

When I did the math before i set it off somehow I came up with 20gigs.

Originally Posted by devildog561

When I did the math before i set it off somehow I came up with 20gigs.

I don't see the relevance of posting this here, as your math is obviously untrue and whatever explanation you have for it is not necessary.

Originally Posted by devildog561

The only one i understand is the first one and i fixed that.

I gave you a link for the only part that would be difficult to google. Everything else is easily google-able. For reference:

- page for #defines: Preprocessor directives - C++ Documentation
- and I already gave you the link to the ASCII chart, but a quick explanation would be:

Characters (a,b,c,etc..) are represented in memory by arrays of numbers. Every character has its own number, and as you probably already know, numbers can be iterated through using for loops. A for loop running from 30 to 39, and then with a "printf("%c")", will print out the representations for those numbers, being 0,1,2,3,etc...

Try it like this... (tested)

Code:

// instant passwords
#include <stdio.h>
#include <time.h>
#include <stdlib.h>

int main (void)
  {
    int num, i;
    char pass[16] = {0};
    FILE *f;
   
    srand(time(0));

    printf("How many passwords do you need (1 - 1000) : ");
    scanf("%d",&num);    

    f = fopen("passwords.txt","w");
    if (!f)
      { 
         printf("Can't open the output file");
         exit(1);
      }

    while (num > 0)
      {
         for(i = 0; i < 15; i++)
            pass[i] = (rand() % ('z' - ' ')) + ' ';
         pass[15] = 0;       
         fprintf(f,"%s\n\n",pass);
         num--;
      }

   fclose(f); 
   printf("Done\n\n");
   return 0;
}