2

I am trying to run a very simple program to glow LEDs in a certain fashion, I connected 9 LEDs to the GPIOs or digital pins, 2 To 10, via 220 Ohm resistors; when I am running the program it is hanging the Arduino after some time interval and LEDs stops glowing, not sure if it is a hardware issue or some bug in the software/code.

Here is the code:

int outGPIOsarr[9] = {2,3,4,5,6,7,8,9,10};

void setup() {


for(int i=0; i<10; i++)
pinMode(outGPIOsarr[i], OUTPUT);
}


void loop() {


for(int i=0; i<10; i++) 
 {
digitalWrite(outGPIOsarr[i],HIGH);
delay(10);
 }


for(int i=0; i<10; i++) 
 {
digitalWrite(outGPIOsarr[i],LOW);
delay(10);
 }


}
Ashish Jog
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1 Answers1

3

This is the UB!

The indexes in array in C++ counts from 0;

So, the last index in your array of 9 elements is 8.

All cycles must stop at 8. Yours are stops at 9.

Access beyond the existing element in the array is the Undefined Behavior - it hangs the MCU.

gbg
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