Boolean data type

A Boolean data type is a representation of data used in computer programming that corresponds to two possible values: true or false. In some cases, true or false can be represented by the binary integers 0 and 1 or by the values on and off. In programming, Boolean data is used to instruct a program on its next task if a specific condition is met. For example, if a program needs a particular task to be completed, it would move on to the next step if the Boolean data type for that task was true. If the condition was false, the program would move on to a different task or halt the program completely. Boolean data was first used in programming in the 1950s, but it gets its name from nineteenth-century British mathematician George Boole, who developed the concept of algebraic logic.

Background

George Boole was born in 1815 in Lincoln, England. His father was a shoemaker who was more interested in science and technology than making shoes. While this led to some financial struggles for the family, it also instilled a love of learning in Boole. Boole began teaching himself mathematics and foreign languages. He started working as a teacher at age sixteen and opened his own school at nineteen. In 1849, he became a professor at Queen’s University in Cork, Ireland.

In 1847, Boole began adapting mathematical concepts to the philosophical discipline of logic. He wrote The Mathematical Analysis of Logic, in which he argued that mathematics was better suited for illustrating logic than philosophy. In 1854, he expanded on his ideas in his book An Investigation of the Laws of Thought, which further supported his idea that math was the best way to illustrate logic. In its basic form, Boole’s method used mathematical formulas to represent logical arguments, with the binary value of 1 representing “true” and 0 representing “false.” His ideas are often cited as the foundation of algebraic logic, also known as Boolean algebra.

Overview

Almost a century after Boole’s death in 1864, his ideas of logic became a fundamental piece of a relatively new scientific pursuit, computer programming. Although primitive programming languages had been invented in the nineteenth century for mechanical devices, the first true programming languages did not originate until the 1940s with the introduction of electronic computers.

From the earliest electronic computers to the more advanced models, computers are machines that need to be given a set of simple instructions to complete a task or operation. These instructions, known as computer programs, are a logical series of steps that a computer must process to move from one task to the next. In 1951, an engineer at Bell Labs in New Jersey noticed that George Boole’s mathematical logic was well-suited for computer programming and used it as part of the program for a system used by the US Air Force. The first use of Boolean data in a programming language was in 1960 when it was used in ALGOL60, which stands for an algorithmic language developed in that year. In the mid-2020s, Boolean data was used in the majority of programming languages, including Java, Python, C++, and Swift.

The Boolean data type is one of several basic data types used by computers to determine the value of a specific data point. Whole numbers, also known as integers, are non-decimal numbers and can be either positive or negative. Real numbers, also called floats, can represent fractional numbers and can also be positive or negative. For example, 2, –10, 36, and 320 are whole numbers, while 5.5, –7.6, and 67.333333 are real numbers. Characters are single elements that can consist of letters, digits, or symbols. Characters can also be combined with other characters in a data type known as a string.

In the Boolean data type, values are represented in just two states: true or false. In some cases, true and false can also be represented as yes/no, on/off, or in binary as 1/0, with 1 representing true and 0 standing for false.

When running a program, a computer looks for Boolean values to see if it can proceed to the next step. For example, in the modern era, usernames and passwords must meet certain security standards to be accepted. If a person has a username of JohnDoe42 and a password of ABCDEFG42, the program would look to see if the person typed in JohnDoe42. If the answer was “true,” the program would move on to the next step. Perhaps the password must consist of at least eight characters and contain a number. The program would look for eight or more characters, if the data value was again “true,” it would move on to see if it had a number. If that were “true” it would move to the next step, verifying whether the given password is ABCDEFG42. If the answer to that is also “true,” the program would allow the user access. If at some point the person types in a wrong value, the program may move to a step that informs the user of the error or stop the login process altogether.

A more complex use of Boolean data may use a conjunction known as an operator to add parameters to a logic statement. For example, AND looks for two values that must both be present in a statement. For example: “Is the username JohnDoe42 AND the password ABCDEFG42?” In this case, if “true,” the program may move to the next step.

The operator OR looks for one or the other of the values to be present, so if either value is present, the Boolean data type will be “true.” The value NOT requires that neither of the selected values be present, so a “true” value will only occur if neither of the selected values is present. Even more complex value sets combine these operators to set up more specific parameters.

In some cases, the Boolean data type cannot be defined and the data type is set to null. Boolean data can only be true or false, so null is only applicable when the data value does not exist. For example, a program designed to monitor earthquake threats may search for seismic readings. If a reading is detected, the value would be “true.” If it is not detected, it would be “false.” However, many areas are not earthquake prone and have no seismic equipment. In this case, the value would be recorded as “null.”

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