float compare in C

.c

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

struct v3d {
  float x, y, z;
};

struct v3d make(float x, float y, float z) {
  struct v3d ans;
  ans.x = x;
  ans.y = y;
  ans.z = z;
  return ans;
}

struct v3d normalize(struct v3d in) {
  float d2 = in.x * in.x + in.y * in.y + in.z * in.z;
  float d = sqrtf(d2);
  in.x /= d;
  in.y /= d;
  in.z /= d;
  return in;
}

void assert_equal(float a , float b) {
  if (a == b) {
    printf("%f and %f are equal\n", a, b);
  } else {
    printf("%f and %f are not equal\n", a, b);

  }
}

int main() {
  struct v3d u = make(3, 1, 2);
  struct v3d v = make( 0.8017837,  0.2672612,  0.5345224);
  struct v3d n = normalize(u);
  assert_equal(n.x, v.x);
  assert_equal(n.y, v.y);
  assert_equal(n.z, v.z);
  return 0;
}

.txt

0.801784 and 0.801784 are equal
0.267261 and 0.267261 are not equal
0.534522 and 0.534522 are not equal