Question

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What is the difference between these (bCondition == NULL) and (NULL==bCondition)?

please see the below code:-

if(myVariable==5)
   {
     //some logic
   }

one of my friends says that this is not a good way to write the code as its not per guidelines, however he dont have any reason to it. Is there is a chance of exception with above code or accidental modification?? According to him the better way would have been

if(5==myVariable)
       {
         //some logic
       }

please let me know which is a better way and why??? Do provide links if u have any.

Answer 1

The only reason to write:

5 == variable

instead of

variable == 5

is that in the former case if you incorrectly put an assignment (single =) in place you will get a compile time error because you are trying to overwrite a constant.

However any decent compiler will give you a warning if you do:

if (variable = 5)

so IMHO it’s not worth worrying about. I always use the latter if (var == num) form.

---

However in Java there is a common pattern that is worth using. When testing a string for equality, one should use:

if ("constant".equals(variable)) { ... }

instead of:

if (variable.equals("constant")) { ... }

since the latter can trigger a null pointer exception, and the former cannot.