Programming Variables and Types

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Questions and Answers

What does the 'int' keyword indicate about the variable cans_per_pack?

It is a reference to another variable.

It can hold floating-point values.

It is used to hold integer values. (correct)

It is an array of integers.

Which of the following correctly follows the rules for variable names?

2ndVariable

variable$price

my variable

variable_price (correct)

What is the purpose of using descriptive names for variables?

To clarify the variable's function. (correct)

To confuse other programmers.

To prevent variable declaration.

To make the code more complex.

Which of the following is NOT a valid variable name according to the rules?

variable-name Signup and view all the answers

What should you avoid when naming a variable?

Starting with a number. Signup and view all the answers

What is a number literal?

A fixed value written by a programmer. Signup and view all the answers

Which statement correctly describes variable name sensitivity in C++?

Variable names are case-sensitive. Signup and view all the answers

Why should the variable name 'cv' be avoided in favor of 'can_volume'?

It does not convey the variable's purpose. Signup and view all the answers

What is a characteristic of reserved words in C++?

They have special meanings in the language. Signup and view all the answers

What does an assignment statement do in C++?

Replaces the value of an existing variable. Signup and view all the answers

How is an assignment statement formatted in C++?

variable_name = value; Signup and view all the answers

What differentiates a variable definition from an assignment statement in C++?

A variable definition allocates memory, while an assignment statement does not. Signup and view all the answers

In the expression 'cans_per_pack = 8;', what does the '=' sign represent?

An instruction to assign a value. Signup and view all the answers

What can you use to change the value of a variable besides an assignment statement?

Inputting new data into it. Signup and view all the answers

Which statement is true regarding the variable 'cans_per_pack' after executing 'cans_per_pack = 8;'?

It will store the value 8. Signup and view all the answers

What is NOT a method to change a variable's value in C++?

Using a variable definition. Signup and view all the answers

What happens to the value of counter after executing the statement 'counter = counter + 2' when counter is initially set to 11?

Counter becomes 13 Signup and view all the answers

In the assignment statement 'counter = counter + 2', what is the first step in the execution process?

Look up the current value of counter Signup and view all the answers

What does the expression 'counter + 2' represent in the context of incrementing counter?

The new value to be assigned to counter Signup and view all the answers

When setting up an input for user data, how is the input '2 6' processed?

Two separate integer values, 2 and 6 Signup and view all the answers

What is the purpose of a manipulator in output formatting?

To round and format displayed values Signup and view all the answers

Which of the following is NOT a step in the assignment of 'counter = counter + 2'?

Display the sum immediately Signup and view all the answers

What result will be stored in the variable 'average' after executing 'double average = (s1 + s2 + s3) / 3' if s1, s2, and s3 are 2, 4, and 6 respectively?

4.0 Signup and view all the answers

Which operation is performed immediately after looking up the current value of counter?

Add 2 to the current value of counter Signup and view all the answers

Study Notes

Variable Definitions

Variable definitions must start with a letter or underscore, and the remaining characters can include numbers or underscores.
Spaces are not permitted, use underscores instead.
Variables names are case-sensitive, so can_volume and can_Volume are different.
Do not use reserved words as variable names, like double or return.

Number Types

Whole numbers are integers.
Fractional values, known as floating-point numbers, can be expressed in scientific notation using the letter e, which represents 10 to the power of.

Variable Names

Use descriptive names that explain the purpose, such as can_volume, instead of terse short names like cv.

The Assignment Statement

The contents in variables can change over time.
An assignment statement stores a new value in a variable, replacing the previously stored one.
An assignment statement does not mean the left hand side is equal to the right hand side, it's an instruction to copy the value of the expression on the right into the variable on the left.
Variable names are case-sensitive, meaning can_volume and can_Volume are considered different names.

Formatted Output

Manipulators are used in cout to specify how values should be formatted for display.
You can use the setprecision manipulator to round off displayed values for output.

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Description

This quiz covers essential concepts of variable definitions, types of numbers, and naming conventions in programming. Understand the rules for creating variables, including case sensitivity and reserved words, as well as how assignment statements work. Perfect for students learning programming basics.