Global Variable
Global Variable
A global variable is a variable declared outside of any function, making it accessible to all functions within the program. Global variables can be used to share data between functions, but also have the potential to cause naming collisions and unintended side effects.
What does Global Variable mean?
A global variable is a variable that has global scope, meaning that it can be accessed from any function or Block of code within a program. Global variables are typically declared outside of any function or block of code, and they can be accessed by using their name without the need for any special syntax.
Global variables are often used to store Data that is shared between multiple functions or blocks of code. For example, a global variable might be used to store the current user’s name, or the current state of a game. Global variables can also be used to store constants, or data that does not change throughout the execution of a program.
Global variables can be a powerful tool for organizing and structuring code. However, they can also be a source of errors if they are not used carefully. For example, if a global variable is accidentally modified by multiple functions, it can lead to unexpected behavior.
Applications
Global variables are used in a wide variety of applications, including:
- Operating systems: Global variables are used to store information about the system, such as the current time, the current user, and the current working Directory.
- Databases: Global variables are used to store information about the database, such as the database name, the database user, and the database password.
- Games: Global variables are used to store information about the game, such as the current level, the current score, and the current player.
- Web browsers: Global variables are used to store information about the web browser, such as the current URL, the current page title, and the current cookies.
History
The concept of a global variable has been around since the early days of programming. However, the term “global variable” was not coined until the 1960s. The first Programming Language to support global variables was FORTRAN, which was released in 1957.
Global variables have been a controversial topic since their inception. Some programmers argue that global variables are a bad practice, and that they should be avoided whenever possible. Others argue that global variables are a necessary evil, and that they can be used to improve the efficiency and organization of code.
Despite the controversy, global variables remain a common feature in many programming languages. They are a powerful tool that can be used to improve the efficiency and organization of code. However, they should be used carefully to avoid errors.