Question

Give one good reason that you should not use global variables in a program.

Short answer

Answer: One should avoid using global variables in a program primarily due to their potential to cause unintended side effects and make the code harder to maintain. Global variables are accessible throughout the entire program, which can lead to conflicts or unexpected behavior, and make debugging more difficult. Instead, using local variables and passing them as arguments to functions can help maintain a more manageable and organized code.

Step-by-step solution

Understanding Global Variables

Global variables are variables that are accessible throughout the entire program, regardless of the function or block of code they are in. They can be used by any part of the code and modified at any time.

Primary Reason to Avoid Global Variables

The main reason to avoid using global variables is that they can lead to unintended side effects and make the code harder to maintain. They can be accessed and modified from any part of the code, meaning that a small change in one part of the program could have unexpected consequences in another unrelated part.

Side Effects and Maintainability

When a global variable is changed, it is difficult to understand how it impacts other parts of the program. This can result in hard-to-debug errors and make the code less maintainable. It also increases the possibility that multiple functions are relying on the same global variable, which could lead to conflicts or unexpected behavior.

Alternatives to Global Variables

Instead of using global variables, it is better to use local variables and pass them as arguments to functions. This ensures that variable access and modifications are limited to the specific scope in which they are defined. If a variable must be shared among different parts of a program, consider using a class or object to encapsulate the variable and its associated behaviors. In summary, one should avoid the use of global variables in a program primarily due to their potential to cause unintended side effects and make the code harder to maintain.