Question

Write a program that inputs a series of integers and passes them one at a time to function even, which uses the modulus operator to determine whether an integer is even. The function should take an integer argument and return true if the integer is even and false otherwise.

Short answer

Define a function to check if a number is even and apply it to each input integer.

Step-by-step solution

Define the Even Function

To solve this problem, the first step is to define a function named `even` that takes an integer as its input. This function will use the modulus operator `%` to check whether the integer is even. An integer is considered even if it is divisible by 2 with no remainder. Thus, if `number % 2 == 0`, the function should return `true`, indicating that the number is even. Otherwise, it should return `false`. In Python, this can be written as follows: ``` def even(number): return number % 2 == 0 ```

Input the Series of Integers

Now, the program must be able to receive a series of integers from the user. You can achieve this by prompting the user to enter the integers, separated by spaces, and then splitting the input string into a list of strings. Each string is then converted to an integer. In Python, this can be done as follows: ``` user_input = input('Enter numbers separated by spaces: ') numbers = list(map(int, user_input.split())) ```

Apply the Even Function to Each Integer

In this step, iterate over the list of integers obtained from the user's input and pass each integer to the `even` function to check if it is even. You can store or display the results as needed. Here's how it can be done in Python: ``` results = [] for number in numbers: result = even(number) results.append((number, result)) ``` This stores tuples of each number with its corresponding boolean result, indicating whether it is even.

Display the Results

Finally, loop through the `results` list and print out whether each number is even or not. This provides a clear output for the user, indicating which numbers are even. In Python, this can be implemented as: ``` for number, is_even in results: status = 'even' if is_even else 'odd' print(f'{number} is {status}.') ```

Key concepts

Modulus Operator

The modulus operator, represented by the symbol `%` in many programming languages, is a crucial mathematical tool for determining remainders. When you use the modulus operator in an expression like `a % b`, it divides `a` by `b` and returns the remainder of that division. This can be incredibly useful for many programming tasks, such as checking if a number is even or odd.

An integer is classified as even if it is divisible by 2 without any remainder; in mathematical terms, an integer `n` is even if `n % 2 == 0`. This means that when you divide `n` by 2, the remainder is zero. For example:

• `4 % 2 == 0` (4 is even)
• `5 % 2 == 1` (5 is odd)

The modulus operator is also useful in applications beyond checking for evenness or oddness, such as cycling through items in a list or limiting values within a certain range.

Python Programming

Python is a versatile and popular high-level programming language known for its readability and simplicity. In Python, defining functions and handling inputs are straightforward tasks due to its easy-to-understand syntax.

One of Python’s strengths is its ability to manage operations with minimal code, allowing you to perform complex tasks simply and effectively. Functions in Python are defined using the `def` keyword, followed by the function name and parentheses containing parameters. For example: ```python def even(number): return number % 2 == 0 ``` This function checks if a number is even using the modulus operator and returns `True` or `False` accordingly. Python's ability to manage complex operations with concise and readable code makes it an excellent choice for programming tasks like this one.

Integer Input Handling

Handling user input in any programming language is crucial, and Python makes this process quite manageable. In the context of this exercise, we need to capture multiple integers from the user, which we can achieve using the `input` function.

When asking for user input, the program waits for the user to type in a response and then presses the enter key. Suppose the user might enter a list of numbers separated by spaces. We can use the `split()` function to break down this input into individual strings. For instance: ```python user_input = input('Enter numbers separated by spaces: ') numbers = list(map(int, user_input.split())) ``` This piece of code will take the string input, split it into a list of substrings based on spaces, and then convert each substring into an integer using the `map` function. Effective handling of user input ensures the program can process data accurately, leading to the desired result.

Boolean Return Values

A boolean value in programming is a type of data that has one of two possible values: `True` or `False`. It plays a fundamental role in decision-making, enabling programs to execute certain pieces of code based on these conditions.

In Python, when we check if a number is even within our `even` function, we use a boolean expression `number % 2 == 0`. If this expression evaluates to `True`, it means our condition (the number being even) is met, and the function returns `True`. Otherwise, it returns `False`. This binary nature allows programs to make decisions efficiently. For instance, based on whether a number is even or odd, the program can proceed to execute different code paths accordingly. Returning boolean values is incredibly useful for functions that need to validate conditions or check for the occurrence of specific states without needing to manage more complex data or operations.