Order of execution for an if with multiple conditionals
c
Solution
This type of evaluation is called short-circuiting. Once the result is 100% clear, it does not continue evaluating.
This is actually a common programming technique. For example, in C++ you will often see something like:
if (pX!=null && pX->predicate()) { bla bla bla }
If you changed the order of the conditions, you could be invoking a method on a null pointer and crashing. A similar example in C would use the field of a struct when you have a pointer to that struct.
You could do something similar with or:
if(px==null || pX->isEmpty()} { bla bla bla }
This is also one of the reasons that it is generally a good idea to avoid side effects in an if condition.
For example suppose you have:
if(x==4 && (++y>7) && z==9)
If `x` is `4`, then `y` will be incremented regardless of the value of `z` or `y`, but if `x` is not `4`, it will not be incremented at all.
Problem
In an if statement with multiple conditionals, is the second conditional executed if the outcome of the first is clear? example: ``` if(i>0 && array[i]==0){ } ``` If I swap the conditionals a segfault may occur for negative values of i, but this way no segfault occurs. Can I be sure that this always works or do have have to use nested if statements?