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Conditional Operators
Conditional-Or: ||

The requirements of our enrollment program have changed again. Certain courses have prerequisites that are satisfied by multiple courses. As long as students have taken at least one prerequisite, they should be allowed to enroll.

Here’s one way we could write the code:

``````if (hasAlgebraPrerequisite) {
// Enroll in course
}

if (hasGeometryPrerequisite) {
// Enroll in course
}``````

We’re using two different `if-then` statements with the same code block. We can be more concise with the OR operator:

``````if (hasAlgebraPrerequisite || hasGeometryPrerequisite) {
// Enroll in course
}``````

The OR operator, `||`, is used between two boolean values and evaluates to a single boolean value. If either of the two values is `true`, then the resulting value is `true`, otherwise the resulting value is `false`.

This code illustrates every combination:

``````true || true
// true
false || true
// true
true || false
// true
false || false
// false``````

### Instructions

1.

Let’s write a message inside the `Reservation()` constructor that warns against bad input.

Our restaurants can’t seat parties of more than `8` people, and we don’t want reservations for `0` or less because that would be silly.

Inside `Reservation()`, write a conditional that uses `||`.

If `count` is less than `1` OR greater than `8` we want to write the following message: `Invalid reservation!`.