computer science Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, ...

and

computer programming Computer programming or coding is the composition of sequences of instructions, called computer program, programs, that computers can follow to perform tasks. It involves designing and implementing algorithms, step-by-step specifications of proc ...

, access level denotes the set of permissions or restrictions provided to a

data type In computer science and computer programming, a data type (or simply type) is a collection or grouping of data values, usually specified by a set of possible values, a set of allowed operations on these values, and/or a representation of these ...

. Reducing access level is an effective method for limiting failure modes, reducing

debugging In engineering, debugging is the process of finding the Root cause analysis, root cause, workarounds, and possible fixes for bug (engineering), bugs. For software, debugging tactics can involve interactive debugging, control flow analysis, Logf ...

time, and simplifying overall system complexity. It restricts variable modification to only the methods defined within the interface to the class. Thus, it is incorporated into many fundamental

software design pattern In software engineering, a software design pattern or design pattern is a general, reusable solution to a commonly occurring problem in many contexts in software design. A design pattern is not a rigid structure to be transplanted directly into s ...

s. In general, a given object cannot be created, read, updated or deleted by any function without having a sufficient access level. The two most common access levels are ''public'' and ''private'', which denote, respectively; permission across the entire program scope, or permission only within the corresponding class. A third, ''protected'', extends permissions to all subclasses of the corresponding class. Access levels modifiers are commonly used in Java as well as C#, which further provides the ''internal'' level. In C++, the only difference between a

struct In computer science, a record (also called a structure, struct, or compound data type) is a composite data structure a collection of fields, possibly of different data types, typically fixed in number and sequence. For example, a date could b ...

and a

class Class, Classes, or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used d ...

is the default access level, which is ''private'' for classes and ''public'' for structs. To illustrate the benefit: consider a public variable which can be accessed from any part of a program. If an error occurs, the culprit could be within any portion of the program, including various sub-dependencies. In a large code base, this leads to thousands of potential sources. Alternatively, consider a private variable. Due to access restrictions, all modifications to its value must occur via functions defined within the class. Therefore, the error is structurally contained within the class. There is often only a single source file for each class, which means debugging only requires evaluation of a single file. With sufficient

modularity Modularity is the degree to which a system's components may be separated and recombined, often with the benefit of flexibility and variety in use. The concept of modularity is used primarily to reduce complexity by breaking a system into varying ...

and minimal access level, large code bases can avoid many challenges associated with complexity.

Example: Bank Balance Class

Retrieved from Java Coffee Break Q&A public class bank_balance Here, the imperative variable ''balance'' is defined as a ''private int''. This ensures other classes, methods and functions cannot accidentally overwrite the variable balance. Instead, they must access the interface for the class ''bank_balance'', whose methods ensure the balance cannot drop below 0.

References

{{Reflist Cybersecurity engineering