Flash cards
Review the key moves
What is the main idea behind C++ Boolean Expressions?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
Which statement best captures the main point of this lesson?
Complete the missing token from the example code.
___ << (x > y); // returns 1 (true), because 10 is higher than 9Put the learning moves in the order that makes the concept easiest to apply.
Boolean Expressions
A Boolean expression is a piece of code that compares values or variables and returns a boolean value: 1 (true) or 0 (false).
Boolean expressions are the foundation of decision making in programming - they let your program decide what to do based on whether something is true or false.
You can use a comparison operator , such as the greater than ( > ) operator, to find out if an expression (or variable) is true or false:
Example
int x = 10;
int y = 9;
cout << (x > y); // returns 1 (true), because 10 is higher than 9Example
cout << (10 > 9); // returns 1 (true), because 10 is higher than 9Or even easier
In the examples below, we use the equal to ( == ) operator to evaluate an expression:
Example
int x = 10;
cout << (x == 10); // returns 1 (true), because the value
of x is equal to 10Example
cout << (10 == 15); // returns
0 (false), because 10 is not equal to 15Store the Result in a Boolean Variable
You can also store the result of a comparison in a bool variable:
x > yNote
It is up to you whether you store the result of a comparison in a boolean variable or use the comparison directly. Storing the result can make your code easier to read, especially if you want to reuse it.