T Level Digital Production, Design and Development Practice Exam 2025 - Free Digital Production and Design Practice Questions and Study Guide

A global variable is one that is declared in the main body of the program, making it accessible throughout the entire program, including within any sub-programs or functions. This means that any part of the code can read from and write to this variable, which facilitates data sharing across multiple functions, leading to better modularity and less redundancy in code.

When a variable is defined in the main body of the program, it typically occupies a wider scope than those defined within individual functions or blocks of code. This wider scope allows the global variable to maintain its value between function calls and be manipulated as needed throughout the program's execution.

In contrast, variables declared within a sub-program are local to that sub-program and cannot be accessed outside of it, emphasizing the distinction between local and global variables. Similarly, a variable limited to only numeric values does not accurately represent the broader capabilities of a global variable. This reinforces the idea that global variables are versatile and can store a variety of data types, depending on how they are defined.