Java arrays of strings. Sorting an array in Java. Two-dimensional array Java

In programming practice, there is a huge number of different sets and types of data that the system can manipulate and with which the programmer can organize the information being processed.

Types of data in programming languages

This is an integral part of most programming languages, which describes the size and characteristics of data placed in a specific memory cell, which ensures the correct operation of programs during the execution of a prescribed operation.

For example, one of the underlying data types is integer variables. They can be both signed 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 floating point analogs that are used to represent real quantities. Finally, the so-called primitive data types include string and character variables and pointers. All this together is a separate linguistic unit.

Data Structures

A higher level of organization in programming is the integration of several units of a primitive data type into a more complex structure. Among the composite types, the so-called Java arrays are considered the most common. You can also select 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 precisely as possible during the initialization phase of the structure. This disadvantage is eliminated in more complex types of data, for example, in lists. Such systems can expand dynamically with the addition of new elements, but access to data in them takes more time.

In most modern programming languages, all these structures are present and play an extremely important role in the functioning of both applied programs and in the work of the ecosystem itself. And Java is no exception.

Java programming language. Basic units

Java is a strongly typed programming language, the bytecode of which 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 the operating system.

In the latest release of the Java language, there are eight primitive types: logical boolean, integer byte, integer, short, long, floating point types , float and double, and character char.

Java-array is a set of data of one type, located in memory one by one and having its own serial number (index), according to which the programmer or the system can access the individual element stored in the array. The indexing starts from zero (the first element) and is incremented by one for each subsequent one. In this case, the Java-array provides random access to data - user code can access any element of the array, regardless of its location within the structure.

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 peculiarity of systems of this type is that Java-arrays can store objects in the same way as they store primitive data types. The most common object in the language are strings. They are sets of symbols organized in a single and immutable memory cell.

An array of Java strings is an ordered set of pointers to other parts of the memory, in each of which the desired object is stored. The user then receives the necessary character set from a remote location in the virtual machine's memory and works with it indirectly.

Two-dimensional arrays (matrices)

This phenomenon, like a matrix, is a two-dimensional array of Java objects or primitives that organizes them according to the "row-column" principle. This data structure is sometimes described as an "array of arrays." This is due to the fact that each row of elements or column is a usual one-dimensional Java-array, and their totality makes up a matrix.

In the two-dimensional variant, each of the vectors can 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 location. The first is the line number in which the required object is located. The second index is the number of the column, or the serial number of the element within the vector. The indexing of elements within two-dimensional structures begins from zero, as in the case of one-dimensional arrays. Therefore, to access the last element of an array of length N, the index [N-1] will be used.

Sorting items

The most common task when working with arrays is sorting. This trivial task at first glance is much more complicated when the number of elements within a vector or matrix increases.

There are a large number of different algorithms designed to sort the elements within a particular structure - the bubble method , the selection sort , the merge or insert method. All methods differ between the speed of the task and the amount of memory needed to store the temporary data and the results obtained during the intermediate operations.

Some algorithms can have a different optimality factor depending on the set of input data. In Java, the sorting of an array can be performed by means of the standard auxiliary class Arrays, which has a static sort method that sorts elements in ascending order and uses the quick-access method. Nevertheless, this algorithm is unstable, and the execution time can be different even when processing arrays of the same length. This sort is known as the fastest for ordered large random lists. Programmers also have access to all the tools for implementing any other sorting algorithm in accordance with the task parameters and the requirements for the result.