Question

The following statement calls a function named half. The half function returns a value that is half that of the argument. Write the function. result = half(number);

Short answer

Question: Create a function named "half" that takes a single argument (a number) and returns half its value. Answer: To create a "half" function in Python, you can use the following code: ```python def half(number): result = number / 2 return result ``` This function takes a single argument, divides it by 2, and returns the result.

Step-by-step solution

Define the function

To create the function, start by using the "def" keyword followed by the function name "half". Add a pair of parentheses and include the parameter "number" inside them. Then, add a colon to indicate the start of the function's body.

Calculate half the number

Inside the function body, divide the input number by 2 using the division operator ("/"). Store the result in a variable called "result".

Return the result

To return the result of the function, use the "return" keyword followed by the "result" variable.

Test the function

Finally, test the half() function with various input numbers to ensure it's working correctly. For example, call the function with the number 8 and verify that the returned result is 4. Here's the complete function: ```python def half(number): result = number / 2 return result # Test the function test_number = 8 print(half(test_number)) # Should print 4 ``` Remember that this is a Python function. If you need to implement this function in another programming language, the syntax might be slightly different.

Key concepts

Function Implementation

When we talk about function implementation in C++, we refer to the actual writing of the code that makes up the function - the statements that will be executed when the function is called. Just like following a recipe to bake a cake, writing a function requires a clear set of instructions.

In the context of our exercise, we can visualize the function implementation in C++ similar to the Python example provided, albeit with C++ syntax. A typical function implementation includes the function's return type, name, parameters (if any), and the body enclosed in curly braces. For the half function that calculates half of a given number, the implementation in C++ would look like this:

double half(double number) {    double result = number / 2.0;    return result;}

This snippet of code is a simple blueprint of how to create a function in C++. Notice that we've declared the function return type as 'double' because it allows for fractional values, which is important for operations like division that may result in a non-integer value.

Parameter Passing

Parameter passing is essentially how we give our functions the data they need to work with. Think of it like handing over the ingredients to someone who's getting ready to cook - without the ingredients, they can't make the meal. In C++, there are several ways you can pass parameters to functions, but we'll focus on the most direct method used in our exercise: passing by value.

When you pass a parameter by value to a function like 'half', you're giving the function its own copy of the argument to work with. This means that any changes made to the parameter inside the function do not affect the original argument. Here's how you would do it:

int main() {    double number = 100;    double halvedNumber = half(number);    // number remains unchanged}

In this example, when 'half' is called with 'number', it makes a separate copy of 'number' for its own use, calculates the halved value, and then that halved value is passed back out and stored in 'halvedNumber'. The original 'number' remains unaffected in the main function.

Return Type

The return type of a function is the type of data that it sends back to the place where it was called. You can think of it as a function's way of giving a report back to its boss – the return type tells the boss what kind of information to expect. In our half function example, the return type is 'double', meaning it will return a number that can include decimal places.

Returning the correct type is crucial for the subsequent code to handle the result properly. In a C++ function, if you say you will return a 'double', but instead try to return an 'int' or a 'string', the compiler will raise an error. Here's how we specify the return type in the 'half' function:

double half(double number) {    return number / 2.0;}

With this function, when you call 'half(5)', you would expect to get back a value of 2.5. This demonstrates the importance of matching the return type to the kind of operation your function is performing.