# C++ Boolean Expressions

## Boolean Expression

A Boolean expression returns a boolean value that is either `1` (true) or `0` (false).

This is useful to build logic, and find answers.

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 9
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Or even easier:

### Example

cout << (10 > 9); // returns 1 (true), because 10 is higher than 9
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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 10
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### Example

cout << (10 == 15);  // returns 0 (false), because 10 is not equal to 15
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## Real Life Example

Let's think of a "real life example" where we need to find out if a person is old enough to vote.

In the example below, we use the `>=` comparison operator to find out if the age (`25`) is greater than OR equal to the voting age limit, which is set to `18`:

### Example

int myAge = 25;
int votingAge = 18;

cout << (myAge >= votingAge); // returns 1 (true), meaning 25 year olds are allowed to vote!
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Cool, right? An even better approach (since we are on a roll now), would be to wrap the code above in an `if...else` statement, so we can perform different actions depending on the result:

### Example

Output "Old enough to vote!" if `myAge` is greater than or equal to `18`. Otherwise output "Not old enough to vote.":

int myAge = 25;
int votingAge = 18;

if (myAge >= votingAge) {
cout << "Old enough to vote!";
} else {
cout << "Not old enough to vote.";
}

// Outputs: Old enough to vote!
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Booleans are the basis for all C++ comparisons and conditions.

You will learn more about conditions (`if...else`) in the next chapter.

## Exercise:

Fill in the missing parts to print the values `1` (for true) and `0` (for false):

``` isCodingFun = true;
isFishTasty = false;
cout << ;
cout << ;
```

Start the Exercise