The introduction of Array in arduino

Array is a variable that can hold a lot of data, each data can be retrieved by the index address (position) data in the array. Address index in the array default is an integer number that starts from the number 0. So, if we have the data in a variable array 5, the first data on the index address 0, the data of the 2nd address to index-1, and the data ke- 5 on the 4th index address.

To understand more about Array, on the Sketch program under a simpler version than the previous Sketch by utilizing a FOR loop and Array.

// www.ioisalman.com  
// Initialization Number of LEDs
 const int numLED = 4; 
// LED 1,2,3, & 4 so one variable
// the index address 0,1,2,3
 const int pinLED[numLED] = {8,9,10,11};  
 void setup() {   
 // Initialize all LED pins as OUTPUT   
for(int i=0; i<4; i++)
 {     
pinMode(pinLED[i], OUTPUT);   
 } 
}  
void loop() {   
// Turn off all LED   
for(int i=0; i<4; i++)
{     
digitalWrite(pinLED[i], LOW);   
}   
delay(1000);      // Turn on all LEDs gradually dg 1 second pause
   for(int i=0; i<4; i++){ 
digitalWrite(pinLED[i], HIGH);     
delay(1000);
   }
 } 

When compared with the previous Sketch without the description line comment, the Sketch on top is much shorter and more simple.

In Sketch above, the four LEDs contained in one variable is the variable Array pinLED. Each LED can be accessed by index address. Notice in line 9

const int pinLED[numLED] = {8,9,10,11};

Automatically, the index address for each LED depends on the sequence of the pin. Pin 8 is on ke0 index address, pin 9 is in the index to 1, the pin 10 is in the index to 2, and pin 11 is in the index to 3. So to access the pin 8, we can add the brackets and address of the index-0 , as follows:

Pin8 = pinLED[0]

Because the highest index is the number 3, then in each iteration LED should not be more than 3 or <4, note the FOR command follows:

for(int i=0; i<4; i++){ 

Yep, I hope the above explanation Array easily understood. If there is any confusion, please ask questions on the website, the author will gladly answer. Good, then we will further develop Sketch on top of that a little more complex and more interesting the animation. The author provides Sketch Sketch 2.8 and 2.9 to be analyzed and studied:

Sketch 2.8

// Initialize Number of LEDs
const int numLED = 4;
// LED 1,2,3, & 4 so one variable
// The index address 0,1,2,3
const int pinLED [numLED] = {8,9,10,11};

void setup () {
   // Initialize all LED pins as OUTPUT
   for (int i = 0; i <4; i ++) {
     pinMode (pinLED [i], OUTPUT);
   }
}

void loop () {
   // Turn on all LEDs gradually dg 1 second pause
   for (int i = 0; i <4; i ++) {
     digitalWrite (pinLED [i], HIGH);
     delay (500);
   }
  
   // off all LEDs gradually dg 1 second pause
   for (int i = 0; i <4; i ++) {
     digitalWrite (pinLED [i], LOW);
     delay (500);
   }
}

Sketch 2.9

// Initialize Number of LEDs
const int numLED = 4;
// LED 1,2,3, & 4 so one variable
// Dengaan index address 0,1,2,3
const int pinLED [numLED] = {8,9,10,11};

void setup () {
   // Initialize all LED pins as OUTPUT
   for (int i = 0; i <4; i ++) {
     pinMode (pinLED [i], OUTPUT);
   }
}

void loop () {
   // Turn led an index of 0 to 2 one by one
  for (int i = 0; i <3; i ++) {
     digitalWrite (pinLED [i], HIGH);
     delay (200);
     digitalWrite (pinLED [i], LOW);
   }
   // Turn led the index 3 to 1 one by one
   for (int i = 3; i> 0; i -) {
     digitalWrite (pinLED [i], HIGH);
     delay (200);
     digitalWrite (pinLED [i], LOW);
   }
}

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