I have a question about arrays in Arduino. Sorry for my bad English. I want to put numbers in an array, and I think the code below works properly.

However, it doesn't work and corrupted numbers show up in the Serial monitor. Even delay(1000) doesn't work.

If I change ND_MAC[i]=128; to "ND_MAC[i]=126;", it works properly. So I'm wondering if this array is char type, but I designate int to array. How to solve it?

int ND_MAC[7];
char i=0;
void setup() {
void loop() {
  • 6
    First error is iterating outside the array. ND_MAC has 7 elements (0..6). Commented Dec 23, 2016 at 12:02

1 Answer 1


For an array of size 7, the indexes start from 0 (ND_MAC[0]) and end at 6 (ND_MAC[6]) as @MikaelPatel commented.

So the solution to your issue would be changing the condition in for loop to

for(i=0;i<7;i++) //Changed 8 in your code to 7

Here, the loop iterates from i = 0 to 1 < 7 (i.e., till 6) and it should work. :)

  • Oh,I had a terrible mistake...
    – kishida
    Commented Dec 26, 2016 at 12:05
  • Oh,I had a terrible mistake... I followed your help, and then it worked properly. thank you very much!
    – kishida
    Commented Dec 26, 2016 at 12:07
  • @kishida you're welcome.... Commented Dec 27, 2016 at 5:36

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