Question

Give an input statement that will fill the variable the_number (of type \(i n t)\) with a number typed in at the keyboard. Precede the input statement with a prompt statement asking the user to enter a whole number.

Short answer

Answer: The three steps to create an input statement for a variable called 'the_number' are as follows: 1. Declare the variable 'the_number': int the_number; 2. Display the prompt to the user: cout << "Please enter a whole number: "; 3. Get the user input and assign it to the variable: cin >> the_number;

Step-by-step solution

Declare the variable

To declare the variable 'the_number' of type int, we write the following code: int the_number;

Display the prompt

We will create a prompt asking the user to enter a whole number. We can use the 'cout' statement to display the prompt as follows: cout << "Please enter a whole number: ";

Get the user input and assign it to the variable

To get input from the user and assign it to our variable 'the_number', we write the following code using the 'cin' statement: cin >> the_number; Here is the complete code snippet: ```cpp #include using namespace std; int main() { int the_number; cout << "Please enter a whole number: "; cin >> the_number; return 0; } ```

Key concepts

C++ variable declaration

In C++, before you can store a value in a variable, you must declare it. This is known as "variable declaration." This process informs the compiler that you want to create a spot in memory where you will store a value. Each variable needs a type, which indicates what kind of data it will hold, and a name, which is used to identify the storage location.

Here's how you declare a simple integer variable in C++:

• int the_number;

This line consists of:

• Type: "int", which stands for an integer. This means the variable can hold whole numbers. "int" is one of the fundamental data types in C++.
• Name: "the_number", a meaningful identifier you choose for your variable to make your code easy to read and understand.

The semicolon at the end is crucial, as it indicates the end of the statement in C++. Without it, the program won't compile, resulting in an error.

C++ user input

In many programs, you need to gather information from the user. C++ provides tools to facilitate this interaction. The most common tool for this task is the input stream object "cin". This allows you to read data typed by users via the keyboard. To accept input in C++, you use the following syntax:

• cin >> the_number;

The "cin" object is associated with standard input (often the keyboard) and the ">>" operator is used to direct the input into a variable. Here's a step-by-step breakdown:

• "cin" is an object representing the input stream from which you read data.
• > operator: Known as the "extraction operator", it directs the input into the specified variable.
• Variable: "the_number" is where the input data is stored after being entered by the user.

Remember that "cin" only reads data after the user presses 'Enter', making it essential for interactive user-driven applications.

C++ prompt statement

A prompt statement is crucial in any program that requires user input. It instructs the user on what to enter, improving the interaction experience. In C++, you use the "cout" statement to display a prompt message on the screen. The code for displaying a prompt is straightforward:

• cout << "Please enter a whole number: ";

Here's what happens in this line:

• "cout" is the standard output stream used to display information on the screen.
• << operator: Known as the "insertion operator", it sends the content on its right side to the output stream.
• Message: The text string inside the quotes is what the user sees. It's there to clearly communicate what input is expected.

By using prompt statements, you ensure that your program is user-friendly and the user knows exactly how to provide the input requested.