What is better way of using boolean value for conditional statement

Question

I have a boolean variable isExists. I need to check if isExists is true then i have to perform some action otherwise i need to perform other action. I can write conditional code like following

approach-1

if(isExists){
//perform use previous interest
}else{
//create new interest
}

approach-2

if(true == isExists){
//perform use previous interest
}else{
//create new interest
}

In some books approach 2 is used and in others approach-1 is used.

What is the difference and which one is better between these two way of checking conditional statement for boolean

I would use `if (((true == isExists) == true) == true)`, just to be really sure ;-) — JB Nizet, Jan 10 '14 at 08:25
what is the difference? Well there is no difference. Same difference :) — Hrishikesh, Jan 10 '14 at 08:25
That said, using `if (exists)` or `if (isExisting)` would be even better. isExists doesn't look like correct English to me. — JB Nizet, Jan 10 '14 at 08:26
@JBNizet And it correct english to me it is `if(isExists()){}` ;) — Suresh Atta, Jan 10 '14 at 08:34
with 18k reputation, I seriously think OP has incidentally asked this question by mistake — DnR, Jan 10 '14 at 08:34
in java i would use the first approach only - the second one seems to be used in javascript quite often — Marco Forberg, Jan 10 '14 at 08:47

Ruchira Gayan Ranaweera · Accepted Answer · 2014-01-10T08:31:35.383

3

if(isExists) this is enough and meaning full.

if(true == isExists) here you are checking isExist with boolean true again. No need redundancy.

edited Jan 10 '14 at 08:31

answered Jan 10 '14 at 08:23

Ruchira Gayan Ranaweera

33,712
16
72
110

score 1 · Answer 2 · answered Jan 10 '14 at 08:33

In java if your variable is primitive 'boolean' than it is file but if it is a object of Boolean class than please beware about NPE
Below code can cause NPE.
Boolean b = null; // Not a primitive boolean. if(b) { System.out.println("It is true"); }else System.out.println("It is false");

score 0 · Answer 3 · answered Jan 10 '14 at 08:24

0

if(isExists){
//perform use previous interest
}else{
//create new interest
}

is enough. Thats the advantage of having a boolean variable. If you have only a single one to check, just specifying the name is sufficient.

answered Jan 10 '14 at 08:24

SoulRayder

4,924
5
42
90

score 0 · Answer 4 · answered Jan 10 '14 at 08:25

The result would be the same in both approaches.

It's usually considered better form to use the former, though, for a couple of reasons:

isExists is in itself a boolean value - there's no need to compute another one
The former appraoch seems more natural when read out aloud (or in your head)

score 0 · Answer 5 · answered Jan 10 '14 at 08:27

0

if(isExists)

Because it assign true by default to the variable

answered Jan 10 '14 at 08:27

BeyondProgrammer

873
2
15
31

score 0 · Answer 6 · answered Jan 10 '14 at 08:28

in other words. its just a condition evaluation. The boolen is a boolen is a boolean. So, you dont compare a boolean (true) with true again to find out weather it is true or false. it doesnt hurt, as in, the compiler doesnt complain but it is no difference.

score 0 · Answer 7 · answered Jan 10 '14 at 08:29

0

Version 1 is more readable, especially if we change the name to exists

if (exists) {
...

answered Jan 10 '14 at 08:29

Evgeniy Dorofeev

129,181
28
195
266

score 0 · Answer 8 · answered Jan 10 '14 at 08:33

if(condition)

this checks if the condition is true. basically it does this( i.e. if your boolean is true):

if(condition==true) -> if(true==true) by reading the boolean's value

So for a boolean, it will take it's value and check it against true. Both of your approaches are good, but conventionally the first one is used, since a boolean is named in such a way expressing a fulfilled condition.

What is better way of using boolean value for conditional statement

8 Answers8