How would you create a random string of data 1

[jdechirico]

I have a program that takes data entered from a keyboard and uses it as a random seed value, is there anyway to generate a string of up to 80 characters that could be used in place of data entered from a keyboard?

 

[cpjust]

Use rand() to generate numbers between 0x30 & 0x7E, then cast them into char's...

 

[jdechirico]

cpjust,

any chance you could provide me with "code snippit" that would set a character field, randombytes, to a 80 byte random string?

 

[cpjust]

I believe this should do it.
NOTE: Will only work on an ASCII system. EBCDIC or other systems will need a different method.

char RandomChar()
{
   return (char)((rand() % 78) + 30);
}


int main()
{
   char str[81];
   int i;

   srand(time());

   for ( i = 0; i < 80; ++i )
   {
      str[i] = RandomChar();
   }

   str[80] = '\0';

   return 0;
}

 

[DaveSinkula]

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

char *rand_str(char *dst, int size)
{
   static const char text[] = "abcdefghijklmnopqrstuvwxyz"
                              "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
   int i, len = rand() % (size - 1);
   for ( i = 0; i < len; ++i )
   {
      dst[i] = text[rand() % (sizeof text - 1)];
   }
   dst[i] = '\0';
   return dst;
}

int main (void)
{
   char mytext[10];
   srand(time(0));
   puts(rand_str(mytext, sizeof mytext));
   puts(rand_str(mytext, sizeof mytext));
   puts(rand_str(mytext, sizeof mytext));
   return 0;
}

/* my output
fEKWZmOQ
IYF
NNabfD
*/