Atoll

An atoll (/ˈætɒl/, /ˈætɔːl/, /ˈætoʊl/, /əˈtɒl/, /əˈtɔːl/ or /əˈtoʊl/), sometimes called a coral atoll, is a ring-shaped coral reef including a coral rim that encircles a lagoon partially or completely. There may be coral islands/cays on the rim. The coral of the atoll often sits atop the rim of an extinct seamount or volcano which has eroded or subsided partially beneath the water. The lagoon forms over the volcanic crater or caldera while the higher rim remains above water or at shallow depths that permit the coral to grow and form the reefs. For the atoll to persist, continued erosion or subsidence must be at a rate slow enough to permit reef growth upwards and outwards to replace the lost height.

Usage

The word atoll comes from the Dhivehi (an Indo-Aryan language spoken on the Maldive Islands) word atholhu (Dhivehi: އަތޮޅު, [ˈət̪ɔɭu]), meaning an administrative subdivision.^OED Its first recorded use in English was in 1625 as atollon – Charles Darwin recognized its indigenous origin and coined, in his The Structure and Distribution of Coral Reefs, the definition of atolls as "circular groups of coral islets" that is synonymous with "lagoon-island".

C string handling

The C programming language has a set of functions implementing operations on strings (character strings and byte strings) in its standard library. Various operations, such as copying, concatenation, tokenization and searching are supported. For character strings, the standard library uses the convention that strings are null-terminated: a string of n characters is represented as an array of n + 1 elements, the last of which is a "NUL" character.

The only support for strings in the programming language proper is that the compiler translates quoted string constants into null-terminated strings.

Definitions

A string is a contiguous sequence of code units terminated by the first zero code (\0, corresponding to the null character). In C, there are two types of strings: string, which is sometimes called byte string which uses the type chars as code units (one char is at least 8 bits), and wide string which uses the type wchar_t as code units.

A common misconception is that all char arrays are strings, because string literals are converted to arrays during the compilation (or translation) phase. It is important to remember that a string ends at the first zero code unit. An array or string literal that contains a zero before the last byte therefore contains a string, or possibly several strings, but is not itself a string. Conversely, it is possible to create a char array that is not null-terminated and is thus not a string: char is often used as a small integer when needing to save memory.

Atoll (disambiguation)

An atoll is a type of island.

Atoll or ATOLL may also refer to:

See also