Working with Two LEDs

1const int LED_red = 3;
2const int LED_green = 6;
3
4void setup()  {
5    pinMode (LED_red, OUTPUT);
6    pinMode (LED_green, OUTPUT);
7}
8
9void  loop() {
10    for (int brightness=1; brightness<=255; brightness++)
11    {
12      analogWrite (LED_red, brightness);
13      delay (5);
14    }
15    for  (int brightness=255; brightness>0; brightness--)
16    {
17      analogWrite (LED_green,  brightness);
18      delay (5);
19    }
20    for (int brightness=255; brightness>0;  brightness--)
21    {
22      analogWrite (LED_red, brightness);
23      delay  (5);
24    }
25    for (int brightness=1; brightness<=255; brightness++)
26    {
27      analogWrite (LED_green, brightness);
28      delay (5);
29    }
30}

1const int LED_red = 3;
2const int LED_green = 6;
3
4void setup()  {
5    pinMode (LED_red, OUTPUT);
6    pinMode (LED_red, OUTPUT);
7}
8
9void  loop() {
10    digitalWrite (LED_red, HIGH);
11    digitalWrite (LED_green, LOW);
12    delay (1000);
13    digitalWrite (LED_red, LOW);
14    digitalWrite (LED_green,  HIGH);
15    delay (1000);
16}