Error: CS0200 | Read only array?

error CS0200: Property or indexer `System.Array.Length’ cannot be assigned to (it is read only)

Anybody can answer what is and how i can sove it?
public float floorsSeed;

	void Awake () {
		//DontDestroyOnLoad ();
	}

	// Use this for initialization
	void Start () {
		floorsSeed.Length = Random.Range (5, 10);
		if (floorsSeed.Length == 5) {
			floorsSeed[1] = Random.Range (0000000001, 9999999999);
			floorsSeed[2] = Random.Range (0000000001, 9999999999);
			floorsSeed[3] = Random.Range (0000000001, 9999999999);
			floorsSeed[4] = Random.Range (0000000001, 9999999999);
			floorsSeed[5] = Random.Range (0000000001, 9999999999);
		} else if (floorsSeed.Length == 6) {
			floorsSeed[1] = Random.Range (0000000001, 9999999999);
			floorsSeed[2] = Random.Range (0000000001, 9999999999);
			floorsSeed[3] = Random.Range (0000000001, 9999999999);
			floorsSeed[4] = Random.Range (0000000001, 9999999999);
			floorsSeed[5] = Random.Range (0000000001, 9999999999);
		} else if (floorsSeed.Length == 7) {
			floorsSeed[1] = Random.Range (0000000001, 9999999999);
			floorsSeed[2] = Random.Range (0000000001, 9999999999);
			floorsSeed[3] = Random.Range (0000000001, 9999999999);
			floorsSeed[4] = Random.Range (0000000001, 9999999999);
			floorsSeed[5] = Random.Range (0000000001, 9999999999);
			floorsSeed[6] = Random.Range (0000000001, 9999999999);
			floorsSeed[7] = Random.Range (0000000001, 9999999999);
		} else if (floorsSeed.Length == 8) {
			floorsSeed[1] = Random.Range (0000000001, 9999999999);
			floorsSeed[2] = Random.Range (0000000001, 9999999999);
			floorsSeed[3] = Random.Range (0000000001, 9999999999);
			floorsSeed[4] = Random.Range (0000000001, 9999999999);
			floorsSeed[5] = Random.Range (0000000001, 9999999999);
			floorsSeed[6] = Random.Range (0000000001, 9999999999);
			floorsSeed[7] = Random.Range (0000000001, 9999999999);
			floorsSeed[8] = Random.Range (0000000001, 9999999999);
		} else if (floorsSeed.Length == 9) {
			floorsSeed[1] = Random.Range (0000000001, 9999999999);
			floorsSeed[2] = Random.Range (0000000001, 9999999999);
			floorsSeed[3] = Random.Range (0000000001, 9999999999);
			floorsSeed[4] = Random.Range (0000000001, 9999999999);
			floorsSeed[5] = Random.Range (0000000001, 9999999999);
			floorsSeed[6] = Random.Range (0000000001, 9999999999);
			floorsSeed[7] = Random.Range (0000000001, 9999999999);
			floorsSeed[8] = Random.Range (0000000001, 9999999999);
			floorsSeed[9] = Random.Range (0000000001, 9999999999);
		} else if (floorsSeed.Length == 10) {
			floorsSeed[1] = Random.Range (0000000001, 9999999999);
			floorsSeed[2] = Random.Range (0000000001, 9999999999);
			floorsSeed[3] = Random.Range (0000000001, 9999999999);
			floorsSeed[4] = Random.Range (0000000001, 9999999999);
			floorsSeed[5] = Random.Range (0000000001, 9999999999);
			floorsSeed[6] = Random.Range (0000000001, 9999999999);
			floorsSeed[7] = Random.Range (0000000001, 9999999999);
			floorsSeed[8] = Random.Range (0000000001, 9999999999);
			floorsSeed[9] = Random.Range (0000000001, 9999999999);
			floorsSeed[10] = Random.Range (0000000001, 9999999999);
		}
	}

void Start () {
floorsSeed = new float[Random.Range (5, 10)];
for( int i = 0 ; i < floorsSeed.Length ; ++i )
floorsSeed = Random.Range (0000000001, 9999999999);

  • }*