Example
All looping constructs allow the use of break and continue statements. They affect the immediately surrounding (innermost) loop.
Basic Loop Control
break terminates the loop:
for x in 0..5 {
if x > 2 { break; }
println!("{}", x);
}
0
1
2
continue finishes the current iteration early
for x in 0..5 {
if x < 2 { continue; }
println!("{}", x);
}
2
3
4
Advanced Loop Control
Now, suppose we have nested loops and want to break out to the outer loop. Then, we can use loop labels to specify which loop a break or continue applies to. In the following example, 'outer is the label given to the outer loop.
'outer: for i in 0..4 {
for j in i..i+2 {
println!("{} {}", i, j);
if i > 1 {
continue 'outer;
}
}
println!("--");
}
0 0
0 1
--
1 1
1 2
--
2 2
3 3
For i > 1, the inner loop was iterated only once and -- was not printed.
Note: Do not confuse a loop label with a lifetime variable. Lifetime variables only occurs beside an & or as a generic parameter within <>.
