0based

0based, short for zero-based indexing, is the convention in which the first element of an ordered sequence is assigned the index 0. This approach is standard in many programming languages and data structures.

Under 0based indexing, a sequence of length N is addressed from 0 to N-1. For example, in C, an array A with N elements is accessed as A[0], A[1], ..., A[N-1]. In Python, lists follow the same convention, with A[0] the first element and A[-1] the last.

Widely used languages include C, C++, Java, JavaScript, Python, Go, and Rust. Some languages favor other indexing schemes; for instance, Lua, R, MATLAB, and Fortran use one-based indexing for their core arrays or offer flexible bounds.

Historically, zero-based indexing has roots in early languages such as BCPL and C, where addressing an element was naturally modeled as a pointer plus offset. It simplifies pointer arithmetic and offset calculation (index i corresponds to i times the element size).

Advantages: predictable range from 0 to N-1, alignment with memory addressing, simplified loops. Potential drawbacks: off-by-one errors when converting from mathematical notation or user expectations; when interfacing with one-based datasets, extra conversion may be needed. Negative indexing is available in some languages (e.g., Python) but not universally.

While widely adopted, the term 0based is primarily used in technical contexts to describe the indexing convention.