I hope it's usefull.

I am new to programming an this is a password file generator i made. I don't know how big it is i stopped it at 75GBs.

Code:

---


 #include <stdio.h>

int main()
{
  FILE *f;
  char a[95]="abcdefghijklmnopqrstuvwuxyzABCDEFGHIJKLMNOPQRSTUVWXY`Z1234567890-=[];',./~!@#$%^&*()_+{}|:<>?";
  char c;
  int b[8];

  f=fopen( "password.txt", "w" );
  printf( "Are you sure you wan't to make this file its almost 20GB?(y/n)\n" );
  printf( ">>" );
  scanf( "%c", &c );
  switch ( c ) {
  case 'y':
    for ( b[1] = 0; b[1] < 95; b[1]++ ) {
    for ( b[2] = 0; b[2] < 95; b[2]++ ) {
      for ( b[3] = 0; b[3] < 95; b[3]++ ) {
      for ( b[4] = 0; b[4] < 95; b[4]++ ) {
        for ( b[5] = 0; b[5] < 95; b[5]++ ) {
        for ( b[6] = 0; b[6] < 95; b[6]++ ) {
          for ( b[7] = 0; b[7] < 95; b[7]++ ) {
          for ( b[0] = 0; b[0] < 95; b[0]++ ) {
            fprintf( f, "%c%c%c%c%c%c%c%c\n", a[b[1]], a[b[2]], a[b[3]], a[b[4]], a[b[5]], a[b[6]], a[b[7]],a[b[0]] );
          }
          }
        }
        }
      }
      }
    }
    }
    break;
  case 'n':
    printf( "Good bye.\n" );
    break;
  default:
    break;
  }
  return 0;
}

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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.

Quote:

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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.

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

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.

Quote:

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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.

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

Quote:

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Originally Posted by devildog561

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

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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.

Quote:

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Originally Posted by devildog561

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

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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;
}

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