function problem in password generator

[lepricaun]

hi guys,
i've written a password generator and would like to make a function of it (for future use), but when i use the function i get into an unending loop, here's the code:

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

void generate_password(int);

int main(void)
{
    int password_length;
    printf("\nThis is a password generator.");
    printf("\nEnter the length of the password: ");
    scanf("%d",password_length);
    printf("\nThe generated password is: ");
    
    generate_password(password_length);
    return 0;
}

void generate_password(length)
{
    int length;
    srand(time(NULL));    
    while (length>0)
    {
        
        int cha;
        cha=rand()%128;
        if((cha>=48 && cha<=57) || (cha>=65 && cha<=90) || (cha>=97 && cha<=122))
        {
           printf("%c",cha);
           length--;
        }
    }
}

problem: when the above code is executed (after compling of course), it gets in a unending loop...

BUT, with the next code the program works fine:

#include <stdio.h> 
#include <stdlib.h>  
#include <time.h>  

int main(void)
{
  srand(time(NULL));
  int cha;
  int length;
  printf("This is a password generator.");
  printf("\nEnter the length of your password: ");
  scanf("%d",&length);
  printf("\nYour generated password is: ");
  while (length>0)
  {
    cha=rand()%128;
    if((cha>=48 && cha<=57) || (cha>=65 && cha<=90) || (cha>=97 && cha<=122))
    {
        printf("%c",cha);
        length--;
    }
  }
  char ch;
  printf ("\nPress any key to continue");
  ch=getch();
  return 0;
}

what did i do wrong by changing the above code to a function?

[Irongeek]

I’m no C expert, but shouldn’t the top line of the function be:

void generate_password(int length)

And without

int length;

My guess is that length is somehow being set to some unholy huge number. I’m messing with it and I’ll let you know what I find.

[lepricaun]

i'll give it a try, and thanks for the help.....

[edit]
gee, i feel stupid! i just made a very stupid mistake:

scanf("%d",password_length);

should be :

scanf("%d",&password_length):

well, thanks for the reply anyway [/edit]

[Irongeek]

Ok, the following works for me in GCC under Cygwin and also in Dev-C++:

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

void generate_password(int);

int main(void)
{
    
    int password_length;
    printf("\nThis is a password generator.");
    printf("\nEnter the length of the password: ");
    scanf("%d",&password_length);
    printf("\nThe generated password is: ");
   
    generate_password(password_length);
    return 0;
}

void generate_password(int length)
{
    srand(time(NULL));
   
    while (length>0)
    {
        
        int cha;
        cha=rand()%128;
        if((cha>=48 && cha<=57) || (cha>=65 && cha<=90) || (cha>=97 && cha<=122))
        {
           printf("%c",cha);
           length--;
        }
    }
}

Enjoy

edit: notice the pass by address in the scanf statement

[lepricaun]

hahaha, you figured it out at about the same time as i did, but thanks for your help anyways

[i2c]

those stupid "&", they catch me out all the time and its the first thing i look for now,

i2c

[lepricaun]

i know what you mean

[Rachid Abdallah]

very nice but these does not support different finds of passwords!!

like :

digits only
letters only
capitalized letters only
special characters

of a combination of all !!

[Rachid Abdallah]

very nice website lepricaun

i found some cool stuff there

check mine >>

[Irongeek]

It does i you modify it. Now stop bringing up old threads unless you have something useful to add (like the code to do what you want).