Global variable

A global variable is a programming term for a variable that is visible to the entire application which it is part of, such as a website or a program. Global variables are commonly used to store information, such as an application identifier, which means the same identifier can be used in multiple places throughout the application. Global variables could also be used to store configuration information which is required for the application to run properly.

Global variables are allocated a memory space in the HEAP as soon as the application begins to run. This means the variable is available to any parts of the application which requires it, even if they are not defined in the same function or module. Global variables can be useful for sharing information between different parts of an application which otherwise wouldn’t have access to each other.

However, it is important to be careful when using global variables. As they are visible application-wide, they can lead to a number of problems, such as potential data conflicts and unexpected behavior. It is therefore recommended to only use global variables if absolutely necessary, and using local variables whenever possible. Additionally, it is generally good practice to only declare global variables at the start of a program, and not afterwards. This can help to reduce the chances of introducing errors.

In summary, global variables can be useful for sharing data between different parts of an application, but they should be used with care due to the potential problems which can arise when they are misused.