rand7 w/ rand5 in C

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

int counter7[7] = {0, 0, 0, 0, 0, 0, 0};

int rand5 ()
{
  return rand () % 5 + 1;
}


int rand7 ()
{
  int r = 0;
  while (r == 0)
    {
      int bits[3] = {0, 0, 0};
      int v = 3;

      for (int i = 0; i < 3; i ++)
    {
      while (v == 3)
        v = rand5 ();

      if (v < 3)
        bits[i] = 1;

      v = 3;
    }

      r = (bits[2] << 2) | (bits[1] << 1) | (bits[0]);
    }

  return r;
}


int main ()
{
  int v;
  srand(time(NULL));

  for (int i = 0; i < 10000000; i++)
    {
      v = rand7 ();
      counter7[v - 1] += 1;
    }


  for (int i =0; i < 7; i++)
    {
      printf("%f\n", counter7[i]/10000000.0);
    }

  return 0;
}


loris@leibniz:~/sandbox$ g++ test.c -o test
loris@leibniz:~/sandbox$ ./test
0.143061
0.142927
0.142746
0.142812
0.143001
0.142784
0.142670