Question

Write the definition of a void function that takes as input a decimal number and outputs 3 times the value of the decimal number. Format your output to two decimal places.

Short answer

Define, calculate, format, and output the result.

Step-by-step solution

Define the Function

Start by defining a void function. In Python, a void function does not return any value and is defined using the `def` keyword.

Take Input Parameter

The function will take one parameter, which is a decimal number. This parameter will be used within the function to perform calculations.

Calculate Three Times the Value

Inside the function, multiply the input decimal number by 3 to get three times its value. Store this result in a variable.

Format the Output

Use Python's string formatting to ensure the result is displayed with two decimal places. You can achieve this by using the `format` method or an f-string.

Output the Result

Print the formatted result. This output showcases the product of the input number multiplied by 3, formatted to two decimal places.

Key concepts

Void Function

In Python, a void function is a function that does not return any value. Unlike functions that produce a result using a `return` statement, void functions simply perform actions. They are typically used to print information, modify data, or cause side effects in a program. A void function is defined using the `def` keyword followed by the function's name and parentheses that include any input parameters. The absence of a `return` statement means that once the function completes its task, it does not pass any value back to the caller. This is useful in situations where returning a value is not necessary, such as when the function's primary purpose is to display information or update global variables.

Decimal Number

A decimal number is a numerical value that contains a decimal point, allowing it to express fractions. In programming, working with decimal numbers is essential, especially when dealing with precise values such as measurements or currency. In Python, handling decimals is straightforward, either through the use of `float`, which is the built-in way to represent decimal numbers, or with the `Decimal` class from the `decimal` module for higher precision requirements. Understanding how decimals work in computer science is crucial because binary representation can sometimes lead to rounding errors, so choosing the correct type of number handling determines the accuracy of calculations.

String Formatting

String formatting in Python allows you to control how output is displayed. It is particularly useful when you need outputs to appear in a specific way, such as showing numbers with a certain number of decimal places. Python offers several ways to format strings. You can use the `%` operator, which is an older method, or utilize the more modern `format` method which offers more readability and flexibility. Another powerful approach is f-strings, introduced in Python 3.6. F-strings allow for inline expressions with an `f` prefix before the string and curly braces `{}` around the variable names. For example, to format a decimal number to two decimal places, you can write: `result = f"{value:.2f}"`. This keeps your output clean and ensures consistency across your program.

Function Parameters

Function parameters are variables listed in a function's definition that provide a means of passing information into the function. They act as local variables within the function, receiving the values supplied by the arguments when the function is called. In Python, you can define a function with different types of parameters:

• Positional parameters, which are required and must be passed in the correct order.
• Keyword parameters, which are named and can be specified in any order.
• Default parameters, which have default values if no argument is provided.
• Variable-length parameters, which accept any number of arguments using `*args` for tuples and `**kwargs` for dictionaries.

Using parameters effectively allows you to write flexible and dynamic functions that can handle various inputs, making your code more reusable and modular.