The && operator combines conditions where both must be true. I'll show you: if (age >= 18 && hasLicense) runs only when age is at least 18 AND hasLicense is true. If the left side is false, the right side is never checked.
This is called short-circuit evaluation and prevents errors when the second check depends on the first. You use && when you need all conditions to be true. Examples: valid range checks x > 0 && x < 100, permission checks isAdmin && isActive, safety checks ptr != nullptr && ptr->isValid().