Unintentionally using
= instead of
== in an
if statement can prove a nasty source of bugs. In the following code,
myFunc is called if
i equals
0:
if (i==0) myFunc(i);
Now suppose that in your haste to meet a deadline, you accidentally wrote:
if (i=0) myFunc(i);
This code would still compile (unless
i is a
const), but in this case
myFunc(i) would always be called, because
i=0 is an assignment that always evaluates to
true, which is not what you intended. If
i is an iterator, even worse things might happen.
To avoid these disasters, get into the habit of writing your tests like this:
if (0==i) ...
This is a perfectly valid—albeit somewhat odd-looking—way of writing tests.
Suppose you forget the == and write =? The code looks like this:
if (0=i) ...
The compiler catches the error correctly. Get in the habit of writing the number on the left hand side of the
== rather than the usual right hand side.
