Question

Write a function definition for a function is_digit that takes one argument of type char and returns a bool value. The function returns true if the argument is a decimal digit; otherwise, it returns false

Short answer

Question: Write a function named 'is_digit' that takes a character as its argument and returns a boolean value depending on whether the character is a decimal digit (0-9) or not. Answer: To achieve this, you can use a function like the one below: ```cpp bool is_digit(char c) { if (c >= '0' && c <= '9') { return true; // The character is a decimal digit } else { return false; // The character is not a decimal digit } } ```

Step-by-step solution

Function Definition

Start by defining the function named 'is_digit' that takes a single argument 'c' of type char. The return type of this function should be bool. bool is_digit(char c) { // Function implementation }

Check If the Character is a Decimal Digit

Inside the function, use an if statement to check whether the input character is within the range of decimal digits (0 to 9). In ASCII, the characters '0' to '9' have continuous values, so we can compare the input character to the characters of '0' and '9'. if (c >= '0' && c <= '9') { // The character is a decimal digit } else { // The character is not a decimal digit }

Return True or False Based on the Condition

Depending on whether the condition is true or false, return the corresponding boolean value. if (c >= '0' && c <= '9') { return true; // The character is a decimal digit } else { return false; // The character is not a decimal digit }

Combine All Steps

Now, combine all the steps in the function definition. bool is_digit(char c) { if (c >= '0' && c <= '9') { return true; // The character is a decimal digit } else { return false; // The character is not a decimal digit } } This is the final implementation of the is_digit function.

Key concepts

Programming with C++

C++ is a powerful general-purpose programming language that supports object-oriented, imperative, and generic programming paradigms. It's widely used for system/software development and game programming due to its performance and efficiency.

When programming with C++, you'll often be creating functions. A function is a set of statements that perform a specific task. Think of a function as a little machine in your program: you feed it some input, it does some processing, and then it spits out a result. In the case of our exercise regarding the is_digit function, the input is a character, and the output is a boolean value indicating whether the character is a digit or not.

Understanding how to implement functions is crucial in C++. The is_digit function is a simple example that shows the beginning steps toward building more complex functionality. By practicing such implementations, students enhance their capability to think logically and learn how to break down problems into smaller, manageable steps.

Function Implementation

Function implementation refers to defining what a function does. In C++, function implementation starts after declaring the function's signature, which includes its name, return type, and parameters.

Thebody of the function houses the logic that executes whenever the function is called. For our is_digit function, its purpose is to determine if a given character is a decimal digit. The function achieves this by checking if the character falls within the ASCII range for numbers 0 to 9. This range check is a common logic used in many programming contexts, showing the essence of conditionals in functions.

One important aspect of function implementation is readability. Writing clear and concise code makes it easier for others (and yourself) to understand and maintain the code in the future. Using meaningful names for functions and variables, like is_digit for our digit-checking function, contributes greatly to this clarity.

Boolean Values in C++

In C++, boolean values are represented by the bool data type, which can hold one of two values: true or false. These values are often the result of logical expressions or comparisons and are fundamental in controlling the flow of a program with conditional statements like if, else, and loops.

The is_digit function leverages boolean values to communicate the result of its digit check. By returning true when the character is a digit and false otherwise, it provides a clear and direct way for other parts of the program to react accordingly. For instance, you might have a larger program where digits lead to one action, while other characters lead to a different one. Boolean values serve as the simple yet powerful junctions that guide the program's decisions, making understanding their use and implications in C++ crucial for budding programmers.