Re: Why is for() less efficient than foreach?

[Bastiaan Veelo via Digitalmars-d-learn]

On Friday, 10 February 2017 at 12:57:38 UTC, biozic wrote:

On Friday, 10 February 2017 at 12:39:50 UTC, Bastiaan Veelo wrote:

    void foreach_loop()
    {
        foreach(n, elem; d[])
            elem = a[n] * b[n] / c[n];
    }

It's fast because the result of the operation (elem) is discarded on each iteration, so it is probably optimized away.

Try:
```
void foreach_loop()
{
    foreach(n, ref elem; d[])
        elem = a[n] * b[n] / c[n];
}
```

Hah, of course.

You can also do:
```
d = a[] * b[] / c[];
```
with no loop statement at all.

Nice.

Thanks.