Can you help me with mathematic calculation, I can't get 670. First I use next algorithm to count lycky integers, and he is quite good as you see:

        double a[8];
        int k = 0;
        bool log = false;
        if (n == 4)
        {
         do
         {
           a[k] = broj % 10;
           broj = broj / 10;
           k = k + 1;
         }
         while (broj != 0);
        if ( a[0]+a[1] == a[2]+a[3])
           log = true;

He gets result 615. After that I calculate how many 4 digit lucky numbers which begins with zero have, and I get 18. That is 615+18 = 643.
Did I miss something?
Obviosly I did, but I can't see, please help!

simply try to use function div_t, u can find it in index.