Can an array have a negative index in C?

C/++ allows negative indexes in multi arrays since it is just a contiguous chunk of memory and index lookups is just pointer arithmetic on it. There. That’s a thing you now know. Languages that implement multi arrays as true multi arrays — arrays of arrays — cannot have negative indexes.

Can an array index be negative?

JavaScript arrays are collections of items, where each item is accessible through an index. These indexes are non-negative integers, and accessing a negative index will just return undefined . Fortunately, using Proxies, we can support accessing our array items starting from the end using negative indexes.

Can I use negative index in C?

So, by this logic, we can access negative indexes in arrays in C.

What does negative index in array mean?

Python programming language supports negative indexing of arrays, something which is not available in arrays in most other programming languages. This means that the index value of -1 gives the last element, and -2 gives the second last element of an array. The negative indexing starts from where the array ends.

Are there negative indexes in arrays in C + +?

C/++ allows negative indexes in multi arrays since it is just a contiguous chunk of memory and index lookups is just pointer arithmetic on it. There. That’s a thing you now know. You can find the code here or on codepen. Also, if you’re wondering whether it would be possible in some other language, that answer is “it depends”.

When to use a negative array index ( arr )?

There’s no magic. It’s a 1-1 equivalence. As always when dereferencing a pointer (*), you need to be sure it’s pointing to a valid address. This is only valid if arr is a pointer that points to the second element in an array or a later element.

Why do negative array indices make sense in memory management?

One can use such a feature to write memory allocation methods that access memory directly. One such use is to check the previous memory block using a negative array index to determine if the two blocks can be merged. I’ve used this feature when I develop a non-volatile memory manager.

When to use an index OF-1 in C?

The other thing is that an array in C is nothing but a contiguous block of memory and indexing starts at 0 so an index of -1 is the location of whatever bit-pattern is before a [0]. Other languages exploit negative indices in a nice way. In Python, a [-1] will return the last element, a [-2] will return the second-to-last element and so on.