Conditionals
Gran parte della sintassi di Rust ti sarà familiare da C, C++ o Java:
- Blocks are delimited by curly braces.
- I commenti di riga iniziano con
//, i commenti di blocco sono delimitati da/\* ... \*/. - Parole chiave come
ifewhilefunzionano allo stesso modo. - L’assegnazione delle variabili viene eseguita con
=, il confronto viene eseguito con==.
if expressions
You use if expressions exactly like if statements in other languages:
fn main() {
let x = 10;
if x < 20 {
println!("small");
} else if x < 100 {
println!("biggish");
} else {
println!("huge");
}
}
In addition, you can use if as an expression. The last expression of each block becomes the value of the if expression:
fn main() {
let x = 10;
let size = if x < 20 { "small" } else { "large" };
println!("number size: {}", size);
}
This slide should take about 5 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.