In computer science, a string is traditionally defined as a sequence of characters, which can include letters, numbers, symbols, and spaces. It can be stored as a literal constant or as a variable, allowing its elements to be mutated and its length to be changed. A string is generally considered a data type and is often implemented as an array data structure of bytes (or words) that stores a sequence of elements, typically characters, using some character encoding).
Strings are used for various purposes, such as storing human-readable text like words and sentences, communicating information from a computer program to the user, and accepting string input from users. They can also store data expressed as characters not intended for human reading. Additionally, strings are used to model real-world data, such as names and addresses, making them a useful tool in many applications. Furthermore, strings are used as input to algorithms for text mining and natural language processing, such as sentiment analysis and named entity recognition.
In programming languages, a variable declared as a string may either cause storage in memory to be statically allocated for a predetermined maximum length or employ dynamic allocation to allow it to hold a variable number of elements. Different programming languages handle single characters and strings differently, with some using single quotes and double quotes to differentiate between them, while others do not differentiate and use either single or double quotes to define string literals.
