Using assignment as a condition expression?

Question

Consider:

if (a=5) {
   /* do something */
}

How does the assignment work as a condition?

Is it based on non-zero value of l-value?

Answer 1

Yes, it is based on the zero/non-zero value which a is assigned. To some people (myself included) it is also considered bad practice to have expressions with side-effects in your code, so the mentioned code fragment would preferably be written as something like

a = 5;
...
if (a != 0) {
    ...
}