控制流程 - While循环

在Sway中的while循环示例

contract;

// While循环
// continue 和 break

abi MyContract {
    fn example_1() -> u64;
    fn example_2() -> u64;
    fn example_3() -> u64;
}

impl MyContract for Contract {
    fn example_1() -> u64 {
        let mut total = 0;
        let mut i = 0;
        while i < 5 {
            i += 1;
            total += i;
        }

        // total = 1 + 2 + 3 + 4 + 5
        total
    }

    fn example_2() -> u64 {
        // continue - 求奇数和
        let mut total = 0;
        let mut i = 0;
        while i < 5 {
            i += 1;
            // 如果是偶数则跳过
            if i % 2 == 0 {
                continue;
            }
            total += i;
        }

        // total = 1 + 3 + 5
        total
    }

    fn example_3() -> u64 {
        // break
        let mut total = 0;
        let mut i = 0;
        while i < 5 {
            i += 1;
            if i > 3 {
                // 退出循环
                break;
            }
            total += i;
        }

        // total = 1 + 2 + 3
        total
    }
}