Question

What are actual and formal arguments? Explain with suitable examples.

Short answer

Formal arguments are placeholders in a function definition, while actual arguments are the real values passed to the function. For example, in `def add(x, y)`, `x` and `y` are formal arguments, and in `add(5, 3)`, `5` and `3` are actual arguments.

Step-by-step solution

Define Formal Arguments

Formal arguments are the variables defined in the function definition that receive the values when the function is called. They act as placeholders for the actual data passed to the function.

Define Actual Arguments

Actual arguments are the real values or data provided to the function during the function call. These are passed to the function to execute the desired operations.

Provide Example of Formal Arguments

Consider a function defined in Python as follows: ```python def add(x, y): return x + y ``` Here, `x` and `y` are formal arguments. They are the placeholders for the data that will be provided when calling the function.

Provide Example of Actual Arguments

Using the previously defined function `add`, let's call it with actual arguments: ```python result = add(5, 3) ``` In this case, `5` and `3` are actual arguments. They are the real values sent to the `add` function to perform the addition.

Summarize Relationship Between Arguments

Formal arguments define the types and number of variables that a function expects, while actual arguments are passed during function invocation and determine the real values the function operates on.

Key concepts

Formal Arguments

In programming, formal arguments serve as placeholders in a function definition. These are the variable names used in the function's header, which lay the groundwork for how the function will handle input data. When you define a function, you specify formal arguments to tell the computer what types of data the function needs to accomplish its task.
For example, in a Python function defined as `def add(x, y):`, `x` and `y` are formal arguments. They don't yet have any value; they are merely positions where data will eventually be stored when the function is executed.
Formal arguments are crucial because they:

• Define what kind of data the function is expected to work with
• Ensure that users of the function know what information they need to provide when calling it
• Help in structuring the logic of the function by providing named references for data

Understanding formal arguments helps you better grasp how functions are organized and how to set up a function to take in data correctly.

Actual Arguments

Actual arguments are the pieces of data you send to a function when you call it. These can be values, variables, or more complex expressions. When the function is called, actual arguments are passed to the function's formal arguments.
Taking our previous example, calling the function as `add(5, 3)` means `5` and `3` are actual arguments. They replace `x` and `y` in the function definition when the function runs.
There are essential things about actual arguments to keep in mind:

• They provide the concrete data which the function will process
• The number and types of actual arguments must match the function's expectations as laid out by its formal arguments
• They can be directly passed values, like numbers, or variables storing those values

This clear role makes actual arguments crucial in determining the input for the function's operations.

Function Definition

A function definition is where you lay out all the details about a new function in your code. This involves specifying a unique name for your function, its formal arguments, and the block of code that will execute when the function is called. The function definition is like setting the blueprint for your desired operation.
Here's a simple breakdown of what a function definition entails:

• Choosing a name: The name should describe what the function does, e.g., `add` for an addition operation
• Specifying formal arguments: Like `x` and `y` in `def add(x, y):`
• Writing the function body: The sequence of statements that perform the operation, such as `return x + y`

The function definition doesn't do anything until the function is actually called. But it sets up everything needed to handle inputs and provide outputs. Properly defining functions enhances code reusability and clarity.

Function Call

A function call is when you actually utilize a function and pass it the necessary actual arguments for it to work with. When a function is called, the program jumps to the function definition, executes its code block, and then returns control back to where the function was invoked, often with some output result.
To continue with the previous example, executing `add(5, 3)` is a function call. Here’s why function calls are important:

• They activate the function's logic and allow the program to actually use the function’s operations
• The actual arguments supplied in a function call determine the specific computation or processing that takes place
• They allow for code modularity, since complex operations can be tucked away in functions and only called when needed

Therefore, understanding function calls is key to effectively employing functions to organize and streamline your code.