Funnily, Zig does allow doing it explicitly like that, just need use while rather for:

    var i: usize = 0;
    while (i <= n) : (i += 1) {
        total += a[i];
    }

That said, perhaps Odin, for which simplicity and readability is guiding principle in its design, is more up your alley. In Odin, can be read:

    for i := 0; i <= n; i += 1 {
        total += a[i]
    }

Exactly same style can be used in Go & V (which is/was? quite infamous here in HN). But in all languages, for this example at least, a foreach-like iteration, i.e.

    for x in a {
        total += x
    }

would be preferred.