User-defined functions allow you to break down a huge programme into smaller chunks, making it easier to comprehend, maintain, and debug. If a programme contains repeating code. A function can be used to incorporate those codes and invoke them when they are needed.
Before invoking and defining the function, declare it with the necessary prototype. The name of the function should be descriptive and meaningful. Maintain the same parameter and return data types when declaring and defining the function. The same data type arguments as in Declaration and Definition should be passed.
Simply use the name of a defined function as a statement anywhere in the code to call it. The above method, greet(), for example, can be called using parentheses. Hello, Universe! If the return statement is missing, all functions default to returning None.