Question

Using the following chart, write a $\mathrm{C}++$ statement that assigns $.10,.15,$ or .20 to commission $10\mathrm{n}$, depending on the value in sales. $$\begin{array}{ll}\text{ SALES }& \text{ COMMISSION RATE }\\ \text{ Up to }\mathrm{\$}10,000& 10\mathrm{\%}\\ \mathrm{\$}10,000\text{ to }\mathrm{\$}15,000& 15\mathrm{\%}\\ \text{ Over }\mathrm{\$}15,000& 20\mathrm{\%}\end{array}$$

Short answer

Answer: The commission rate is 15%.

Step-by-step solution

Declare the sales variable

First, create a variable called 'sales' to hold the sales value. ``` double sales; ```

Input the sales value

Get the sales value from the user as an input. ```cpp cout << "Enter the sales value: "; cin >> sales; ```

Define the commission variable

Declare a variable called 'commission' that will hold the commission rate. ```cpp double commission; ```

Assign appropriate commission rate based on sales

Use if-else statements to define the commission rate based on the sales value entered. ```cpp if (sales <= 10000) { commission = 0.10; } else if (sales <= 15000) { commission = 0.15; } else { commission = 0.20; } ```

Output the commission rate

Display the commission rate using the 'commission' variable. ```cpp cout << "The commission rate is: " << commission * 100 << "%\n"; ```

Key concepts

if-else statements

In C++ programming, the **if-else statements** are a fundamental concept used to make decisions within a program. Essentially, these statements allow the program to choose different paths based on certain conditions.
You can think of if-else as a way for your program to "think" and react differently depending on the input it receives.

• The simplest form of an if-else statement begins with the "if" keyword followed by a condition enclosed in parentheses.
• If the condition evaluates to true, the block of code following the if statement will execute.
• If the condition is false, the program checks any else-if condition or executes the code under "else" if present.

The if-else structure used in the exercise is: ```cpp if (sales <= 10000) { commission = 0.10; } else if (sales <= 15000) { commission = 0.15; } else { commission = 0.20; } ``` Here, three scenarios are checked and the associated blocks are executed based on the condition outcome.

variable declaration

In C++, **variable declaration** is a critical step when programming as it helps to define the storage for data that your program will use. Variables in C++ have a type, a name, and sometimes an initial value.

• The type specifies the kind of data the variable will hold. Examples include `int` for integers and `double` for floating-point numbers.
• You declare a variable by specifying its type followed by the variable name. For instance, double sales; declares a variable named `sales` of type double.

Variable declaration in the provided exercise involves setting up storage for the key pieces of information such as the `sales` and `commission` values, without initially assigning them a value: ```cpp double sales; double commission; ``` This step ensures that C++ knows the kind of data these variables will manage, which allows later operations on these variables according to their types.

user input

**User input** in C++ is often handled through standard input streams. Primary functions deal with capturing user input and incorporating it into your program, making the program responsive to external data.

• The `cin` function is utilized for user input in a console application.
• `cin` requires the `iostream` header file, and it typically works alongside the extraction operator (`>>`) to read data from the standard input device, usually the keyboard.

For instance, getting sales value from the user in the example is done with: ```cpp cout << "Enter the sales value: "; cin >> sales; ``` Here, cout is used to prompt the user, and cin is used to store the entered value in the `sales` variable. This interaction allows the program to cater its responses based on user-provided data.

conditional logic

**Conditional logic** is a cornerstone of programming, allowing programs to make decisions based on different criteria or conditions. In C++ and similar languages, it involves using logical constructs to dictate the flow of execution based on variable states or computed expressions.

• Conditions generally evaluate to either true or false.
• Logical operators like `<`, `<=`, `==`, `!=`, `>`, and `>=` help formulate more complex conditions.
• These conditions directly affect the execution of if-else statements.

In the original exercise, conditional logic is employed to determine which commission rate to assign based on `sales` value: ```cpp if (sales <= 10000) { commission = 0.10; } else if (sales <= 15000) { commission = 0.15; } else { commission = 0.20; } ``` Here, three different scenarios are checked using `<=` to ensure accurate assignment of the commission rate. Conditional logic allows fine-tuned control of the program, enabling dynamic responses based on varying inputs.