What is the array subscript starting from 0?

We will feel that the array subscript starting from 0 very annoying, subscript 0 began to represent the first, subscript 1 is the second, is not feel particularly awkward. So why is it starting at 0?

Int[] A=new int[]{1,2,3,4,5};

Here are 5 values, first we assume that the array of 5 address numbers in memory are 1000,1001,1002,1003,1004, assuming it is for convenience of computation.

At the moment we visit a[0], that is, access to address number 1000,

Think of it, 1000 is the first address of the array, that is, the first value that represents the group 1,1000+0 equals 1000, if the logical subscript also starting from 1 is not 1000+1=1001 access to the second address 2 slightly.

This is why the array starts at 0, because a refers to the first address number in the array, starting at 0, and the 1 addresses that are accessed.