How are strings stored and manipulated in memory?

Strings are stored in memory as a sequence of characters, each character occupying a specific memory location.

In more detail, a string is a data type used in programming, such as an integer and floating point unit, but is used to represent text rather than numbers. It is comprised of a set of characters that can include spaces, digits, alphabets, or special characters. In memory, each character in the string is stored in a sequential memory location. This sequence of memory locations is often referred to as an array of characters. For more on how different data types are understood, see our notes on Understanding Data Types.

The way strings are stored can vary depending on the programming language. For instance, in languages like C and C++, a string is stored as an array of characters ending with a special character known as the null character. This character signals the end of the string. In languages like Python and Java, strings are objects, and they are stored in a contiguous block of memory, with each character taking up a fixed amount of space.

Manipulating strings in memory involves operations such as concatenation (joining two strings), slicing (extracting a portion of a string), and searching (finding a particular character or substring in a string). These operations are performed using built-in functions provided by the programming language. For example, in Python, the '+' operator is used for concatenation, square brackets are used for slicing, and the 'in' keyword is used for searching. A deeper look into the fundamentals of programming can be found in our notes on Introduction to Fundamental Programming Constructs.

It's important to note that some languages treat strings as immutable, meaning they cannot be changed once they are created. In such cases, any operation that appears to modify a string actually creates a new string. For example, in Python, if you try to change a specific character in a string, the language will create a new string with the desired changes, rather than modifying the original string. For a better understanding of how arrays and similar data structures work, refer to our notes on Array Terminology.

IB Computer Science Tutor Summary: Strings are data types in programming used to represent text. They are stored in memory as arrays of characters. Depending on the programming language, the specifics of how strings are stored and manipulated can vary. Operations like concatenation, slicing, and searching are common. Some languages consider strings immutable, meaning they cannot be altered once created.