what kind of language is it, it does not look like the regular C

PaulS:
That code already puts the data in an array. If you don't want to send it to the serial port, don't.

I know that the data collected from A0 pin goes into memory, I just cannot figure out the coding.

Can I transfer the data later for example into array, making sure it does not slow the sampling rate.

if I declare array like this.

int myArray[2000];

how do I put the data into myArray[1], myArray[2], ....., myArray[2000]

thanks