Magic Number
Magic Number
A magic number in computing refers to a fixed numerical constant or value that often appears in source code or system configurations and holds a specific technical or algorithmic significance. Magic numbers are generally used to represent specific values or thresholds without explicitly stating their meaning in the code, making it challenging for others to understand and maintain the code.
What does Magic Number mean?
In computer science, a magic number is a numeric literal in the Code that has no apparent meaning in terms of the program’s logic. It is often used as a placeholder or to improve readability. Magic numbers Make code less maintainable and difficult to understand, as they require the reader to remember their intended purpose.
One example of a magic number is the number 42, which is famously used as the “Answer to the Ultimate Question of Life, the Universe, and Everything” in The Hitchhiker’s Guide to the Galaxy series by Douglas Adams. While this number may be meaningful to fans of the series, it is a magic number in the context of Programming.
Magic numbers can also be used to represent configuration settings or constants. For example, a program may define a maximum number of connections as MAX_CONNECTIONS = 100. While this number may be meaningful in the context of the program, it is still a magic number because it is not immediately clear why the number 100 was chosen.
Applications
Magic numbers are often used in programming because they can make code more readable. For example, the following code Snippet uses a magic number to represent the number of days in a week:
java
int daysInWeek = 7;
This code is more readable than the following, which uses a named constant:
java
final int DAYS_IN_WEEK = 7;
However, the use of magic numbers can make code less maintainable and difficult to understand. If a magic number is changed in the future, it may be difficult to determine why the change was made and what the consequences will be.
History
The use of magic numbers dates back to the early days of programming. In the 1950s and 1960s, programmers often used magic numbers to represent configuration settings or constants. This practice continued throughout the 1970s and 1980s.
In the 1990s, there was a growing awareness of the problems associated with magic numbers. Programmers began to use named constants to represent configuration settings and constants. This practice has become increasingly common in recent years.
Today, the use of magic numbers is generally discouraged. Named constants are a better way to represent configuration settings and constants because they are more readable and maintainable.