Functions and Program Structure

An XJEase program will typically be broken down into smaller reusable functions.

Functions have two sets of parameters: input and output. Input parameters are passed by value: a copy is made to pass to the function. If the function modifies a value, that modification is not visible in the calling function. Output parameters are passed by reference: the calling function passes a variable into the called function and any changes made by the called function are visible to the caller when the called function returns.

Sometimes when passing a large value into a function, it may be preferable to avoid it being copied and so you may choose to pass it as an output parameter instead.

• Function Definition
• Calling Functions
• Function Scopes
• Returning from Functions
• Variable Scope Rules
• External API functions