A. 0
B. -1
C. 2
D. 1
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Explanation :
The first element in an array: Why the index is always zero
The index of the first element in an array, whether it’s an array in JavaScript or an array in any other programming language, has always been zero, ever since the first computers came out. You may have wondered why this was so or what’s the historical reason behind it, but let’s look at why it works that way from a practical perspective as well as from a theoretical one, starting with what happens behind the scenes when you have an array of four elements and ask for its length property (which will return 4)
General explanation
When arrays are created, they're all initialized with a value of 0. That's because they're typically intended to be used as indexes (with each succeeding index holding a specific key of information). Since arrays typically don't use all of their values at once, sometimes you'll find that elements are missing from the start or from the end. In this case, it's possible for multiple indices to point to the same data value.
First vs Last Element
In computer programming, it's common to create a data structure called an array. An array is just a list of objects with a numbered index. The 0 corresponds to the first object in the list, so if you want to access one of those objects you say objectAtIndex(0). You can also use brackets for looping through all elements of the list, or a for-loop for iterating over each position and value.
Initializing Arrays and Why You Shouldn’t
When using arrays, it’s important to note that indexes are assigned from 0. This means if we have a three-element array, our first element is at index 0. The second element at index 1 and the third at index 2. It’s also important to remember that when you set up your array, the first value will automatically be inserted as (index), even if you input a numerical value in another place of your equation like so
Best Practices
One way to avoid naming collisions and achieve a more comprehensible API is by representing each element of an array as a record or struct that contains fields corresponding to its indices. For example, if we wanted to represent a list of people (by name), it might be better to do this:
struct People {
iubians
