Question

Write a statement (or comment) to accomplish each of the following (assume that using declarations have been used): a. State that a program calculates the product of three integers. b. Declare the variables x, y, z and result to be of type int (in separate statements). c. Prompt the user to enter three integers. d. Read three integers from the keyboard and store them in the variables x, y and z. e. Compute the product of the three integers contained in variables x, y and z, and assign the result to the variable result. f. Print "The product is " followed by the value of the variable result. g. Return a value from main indicating that the program terminated successfully.

Short answer

The program computes and displays the product of three integers entered by the user.

Step-by-step solution

State the Purpose of the Program

Add a comment at the beginning of the program to explain its functionality. ```cpp // This program calculates the product of three integers. ```

Declare Variables

Declare the required variables separately with the `int` type. ```cpp int x; // declare variable x int y; // declare variable y int z; // declare variable z int result; // declare variable result ```

Prompt User for Input

Use a statement to ask the user to enter three integers. ```cpp std::cout << "Enter three integers: "; ```

Read Input from User

Read the three integers entered by the user and store them in variables `x`, `y`, and `z`. ```cpp std::cin >> x >> y >> z; ```

Calculate the Product

Compute the product of `x`, `y`, and `z` and store it in the variable `result`. ```cpp result = x * y * z; ```

Display the Result

Output the result of the calculation to the user. ```cpp std::cout << "The product is " << result << std::endl; ```

Return from Main Successfully

Finish the main function by returning 0 to indicate that the program ended successfully. ```cpp return 0; ```

Key concepts

Variables in C++

Variables in C++ are essential for storing data that a program uses during its execution. In C++, a variable is like a container that holds a value. Each variable has a specific type that determines the kind of data it can store. Common variable types include:

• int for integers
• char for characters
• float or double for floating-point numbers

In our exercise, we use `int` to declare four integer variables: `x`, `y`, `z`, and `result`. These variables are declared separately: ```cpp int x; int y; int z; int result; ``` Each statement creates a variable of type `int`, which means it can store whole numbers. When you declare variables, make sure they have meaningful names to make your code easier to understand.

Input/Output in C++

In C++, input and output operations are achieved using streams. Streams make it possible to exchange data between the user and the program. The two main streams used in basic C++ are `std::cin` and `std::cout`. **Input with `std::cin`:** `std::cin` reads data from the standard input, typically the keyboard. To capture multiple values, such as integers, you can chain the input steps using `>>` operator: ```cpp std::cin >> x >> y >> z; ``` This line captures three integers and stores them in `x`, `y`, and `z`. **Output with `std::cout`:** `std::cout` is used for output to the console. It displays data, usually to provide feedback to the user. You use the `<<` operator to send information to the output: ```cpp std::cout << "The product is " << result << std::endl; ``` This command outputs the text followed by the value stored in `result` and ends the line.

Comments in C++

Comments in C++ are notes that programmers add to make the code more understandable. They do not affect how the program runs. There are two types of comments in C++: 1. **Single-line comments:** They start with `//` and continue to the end of the line. For example: ```cpp // This program calculates the product of three integers. ``` This single-line comment explains the purpose of the program. 2. **Multi-line comments:** Begin with `/*` and end with `*/`. They can span multiple lines. ```cpp /* This is a multi-line comment */ ``` Use comments liberally to make your code easier to understand. When you write code, consider those who may read it later, including your future self. Descriptive comments can save a lot of time in understanding code logic.

Basic Arithmetic Operations

Arithmetic operations in C++ are fundamental and allow manipulation of numerical data. The common arithmetic operators include:

• Addition (+): adds two numbers
• Subtraction (-): subtracts one number from another
• Multiplication (*): multiplies two numbers
• Division (/): divides one number by another
• Modulus (%): finds the remainder after division

In our specific exercise, multiplication is used to find the product of three integers stored in variables `x`, `y`, and `z`: ```cpp result = x * y * z; ``` This line of code multiplies the values of `x`, `y`, and `z`, and places the result into the `result` variable. Proper use of arithmetic operators is crucial in performing calculations accurately in programs.