#![allow(dead_code, deprecated, unused_variables, unused_mut)]
use std::ops::ControlFlow;
fn main() {
    let triangular = (1..30)
        .try_fold(
            0_i8,
            |prev, x| {
                if let Some(next) = prev.checked_add(x) {
                    ControlFlow::Continue(next)
                } else {
                    ControlFlow::Break(prev)
                }
            },
        );
    assert_eq!(triangular, ControlFlow::Break(120));
    let triangular = (1..30)
        .try_fold(
            0_u64,
            |prev, x| {
                if let Some(next) = prev.checked_add(x) {
                    ControlFlow::Continue(next)
                } else {
                    ControlFlow::Break(prev)
                }
            },
        );
    assert_eq!(triangular, ControlFlow::Continue(435));
}