عبارات if
You use if
expressions exactly like if
statements in other languages:
fn main() { let x = 10; if x == 0 { println!("zero!"); } else if x < 100 { println!("biggish"); } else { println!("huge"); } }
در کنار این موضوع, میتوانید از if به عنوان یک عبارت با قابلیت بازگشت مقدار هم استفاده کنید. آخرین عبارت توی هر بلاک if اون مقدار و نوع بازگشتی است:
fn main() { let x = 10; let size = if x < 20 { "small" } else { "large" }; println!("number size: {}", size); }
This slide should take about 4 minutes.
Because if
is an expression and must have a particular type, both of its branch blocks must have the same type. Show what happens if you add ;
after "small"
in the second example.
When if
is used in an expression, the expression must have a ;
to separate it from the next statement. Remove the ;
before println!
to see the compiler error.