why I can't use the (? :) operators like if-else statements in Java?

Question

I can define variables using the (? :) operators. But why I can't use it as an if-else statement to execute statements based on a condition?

I tried doing the following:

char first = queue.remove();
(first == 'W') ? women++ : men++;

But did not work.

Because you have to return something into a variable. That is not the same semantics as an if/else statement. — OldProgrammer, Oct 30 '17 at 01:23
Have a look on Java ternary operator for your understanding https://alvinalexander.com/java/edu/pj/pj010018 — Damith, Oct 30 '17 at 01:26
@alfasin I know that but I am asking why I can't use it to run statements. — Mahmoud Hamad, Oct 30 '17 at 01:27
"Why can't I fit the square block into the circular hole?" --- The ternary operator is the wrong tool for the job. — byxor, Oct 30 '17 at 01:27
The general syntax for ternary operator is "result = testCondition ? value1 : value2" that's why you can't perform your statement. — Damith, Oct 30 '17 at 01:30

gdejohn · Accepted Answer · 2017-10-30T04:57:10.460

4

That's called the ternary operator, and it results in an expression, not a statement. Semi-colons follow statements.

The following is valid because it's both a statement and an expression (if the return type of foo is void, then it's only a statement):

foo();

And the following is invalid for the same reason your ternary operator example is invalid (a literal string is only an expression):

"xyzzy";

If you want to execute one statement or another depending on a boolean, use an if-then statement. If you want an expression to take one value or another depending on a boolean, use the ternary operator. They're not interchangeable.

edited Oct 30 '17 at 04:57

answered Oct 30 '17 at 01:24

gdejohn

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Can you elaborate on the differences between expressions and statements in this case (using an example maybe) Thanks – Mahmoud Hamad Oct 30 '17 at 01:31
So expression can be only assigned to variables? – Mahmoud Hamad Oct 30 '17 at 01:33
You can assign an expression to a variable or pass it as an argument to a function that you invoke. – gdejohn Oct 30 '17 at 01:34
I wanna check my understanding. == is an operator, it needs two expressions, right? – Mahmoud Hamad Oct 30 '17 at 01:36

Alexander King · Answer 2 · 2017-10-30T01:29:45.333

0

While if-statement's allow the logical flow of code, the ternary operator is actually an operation that takes three operands. The ternary operator results in an expression, not a statement.

edited Oct 30 '17 at 01:29

answered Oct 30 '17 at 01:28

Alexander King

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The last part of this answer is the exact same as the previous answer. Did you just copy it? – byxor Oct 30 '17 at 01:29
Nope, he just beat me to it. – Alexander King Oct 30 '17 at 01:31

why I can't use the (? :) operators like if-else statements in Java?

2 Answers2