Question

question regarding BOOLEAN operator ‘|’ and ‘||’. The only difference I can find between these two operators is; when using ‘||’ the right side of the expression will not be evaluated if the left side is true.

Outside of person preference why would one use ‘|’ over ‘||’ for boolean testing?

if(true | false)
{
do something
}

vs 
if (true || false)
{
do something
}

Answer 1

It’s primarily an issue if the operation has side effects:

Consider the following:

using(IEnumerator iterator1 = args.GetEnumerator())
using (IEnumerator iterator2 = args.GetEnumerator())
{
    while (iterator1.MoveNext() | iterator2.MoveNext())
    {
        //do stuff
    }
}

Because the MoveNext operations cause side effects it may be important for both sides of the | to be executed regardless of whether the first is true.