What is Global or External variables - Functions in C Programming - C Programming

TL;DR

The concept of global variables allows variables to be accessible across multiple functions.

Transcript

hello friends let's deal with the second storage class of memory type that is global or external storage class where exactly the keyword extern will be used and when do i identify the variable as global variable why do i need these global variables to understand this let's take a simple example assume that i have a main function and i have a functi... Read More

Key Insights

• 🌐 Global variables enable sharing data across functions.
• 🌐 The life of global variables begins with the program.
• 🌐 The keyword "extern" indicates a global variable in multi-file programming.
• 🌐 Global variables improve memory efficiency by avoiding redundant memory allocation.
• 🌐 Global variables have visibility to functions declared after their initialization.
• 👻 Declaring variables as global allows reuse across multiple functions.
• 👣 Global variables are essential for keeping track of data throughout a program.

Questions & Answers

Q: What are global variables in programming?

Global variables are declared outside functions and can be accessed by multiple functions within a program.

Q: How is the life of a global variable defined?

The life of a global variable starts when the program begins execution and ends when the program terminates.

Q: When is the keyword "extern" used for variables?

The "extern" keyword is used to declare a variable as global in a multi-file programming environment to avoid duplicating memory allocation.

Q: How are global variables beneficial in programming?

Global variables allow sharing data across functions, reducing memory duplication and improving code efficiency.

Summary & Key Takeaways

• Global variables are declared outside functions to be accessed by multiple functions.

• They have a life scope starting and ending with the program.

• The keyword "extern" is used to indicate a global variable in multi-file programming environments.