In programming practice, there are a huge number of different sets and types of data that the system can manipulate and with which the programmer can organize the processed information.
Data Types in Programming Languages
This is an integral part of most programming languages, which describes the size and characteristics of the data placed in a specific memory cell, which ensures the correct operation of programs in the process of performing one or another prescribed operation.
For example, one of the underlying data types is integer variables. They can be both iconic and vice versa, and the name itself already conveys information about the contents of a cell of this kind.
In addition to integer variables, there are their floating point counterparts, which are used to represent real values. Finally, the so-called primitive data types include string and character variables and pointers. Together, this represents a separate linguistic unit.
Data structures
The higher level of organization in programming is the combination of several units of a primitive data type into a more complex structure. Among composite types, the so-called Java arrays are considered the most common. You can also highlight lists, tuples, stacks, and queues.
The main difference between arrays is that they provide random access to their elements. However, the difficulty lies in the fact that the size must be specified as accurately as possible at the initialization stage of the structure. This flaw is eliminated in more complex data types, for example, in lists. Such systems have the ability to dynamically expand with the addition of new elements, however, access to data in them takes a greater amount of time.
In most modern programming languages, all these structures are present and play a crucial role in the functioning of both application programs and the ecosystem itself. And Java is no exception.
Java programming language. Basic units
Java is a strongly typed programming language whose bytecode is executed inside the virtual machine, which allows you to perform operations and get the same result, regardless of the architecture of the computing environment and operating system.
In the latest release of the Java language, there are eight primitive types: boolean boolean, integer byte, integer, short, long, types of floating-point numbers, represented by float and double, and character char.
A Java array is a set of data of the same type, located in memory one after another and having its own serial number (index), by which a programmer or system can access a single element stored in the array. Numbering in the index starts from zero (the first element) and increases by one for each subsequent one. At the same time, the Java array provides random access to data - user code can access any element of the array, regardless of its location within the structure.
The objects
Do not forget that Java is primarily an object-oriented programming language. Therefore, these elements are an integral part of the memory model. A feature of this type of system is that Java arrays can store objects in the same way as they store primitive data types. The most common object in a language is strings. They are sets of characters organized in a single and immutable memory cell.
An array of Java strings is an ordered set of pointers to other sections of memory, each of which stores the desired object. Thus, the user receives the required character set from a remote location in the virtual machine’s memory and works with it indirectly.
Two-dimensional arrays (matrices)
Such a phenomenon as a matrix is a two-dimensional array of Java objects or primitives, organizing them on a row-column basis. This data structure is sometimes described as an "array of arrays." This is due to the fact that each row of elements or a column is a regular one-dimensional Java array, and their combination makes up a matrix.
In the two-dimensional version, each of the vectors may have its own length, different from the others. When accessing a single element of an array, two indexes are used to indicate the location of the desired memory cell. The first is the line number in which the required object is located. The second index is the column number, or the serial number of the element inside the vector. Indexing of elements within two-dimensional structures starts from scratch, as is the case with one-dimensional arrays. Therefore, to refer to the last element of an array of length N characters, the index [N-1] will be used.
Sort Items
The most common task when working with arrays is sorting. This seemingly trivial task is much more complicated when the number of elements inside a vector or matrix increases.
There are a large number of different algorithms designed to sort elements within a given structure - the bubble method , sort by selection, select by merge, or insert method. All methods differ among themselves in the speed of the task and the amount of memory needed to store temporary data and results obtained during intermediate operations.
Some algorithms may have different optimality coefficients depending on the set of input data. In Java, array sorting can be done using the standard Arrays helper class, which has a static sort method that sorts items in ascending order and uses a quick select method. However, this algorithm is unstable, and its execution time may differ even when processing arrays of the same length. This sort is known as the fastest for ordered large random lists. Programmers are available all the means to implement any other sorting algorithm in accordance with the parameters of the task and the requirements for the result.