Using Global Variables

Global Variables

Global variables are used in applications in programming. There are advantages and disadvantages to using these variables. Using global variables has its advantages in some forms of applications, while using them in others would make using them more difficult.
Global variables are useful when you need to share a function with all functions in an application. Global variables can be easier to identify in an application by giving them a unique name, so that other programmers can see they are working with a global variable when maintaining your application. On small programs such as widgets or gadgets it may be easier to use global rather than passing around local variables. Using a global variable means that other functions cannot update it. Another advantage to global is that they can be accessed from anywhere in the program.
Some are also disadvantages to using global variables. Global variables can create mutual dependencies, with an increase in dependencies the complexity of the code increases. Any function can access a global variable in the program so a change in the program at one point can change values everywhere. Global variable also slow down performance speed a little. Using global variables makes reusing parts of the script impossible. Global variables also make tracking a bug much harder.
When declaring a global variable in a flowchart, you would but the variable in the main part of the program, hence the box the other functions branch off of. For local variables, you would put those in boxes where separate function are executed.