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Quick question: What exactly does this line of code do?

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Started by S8N February 14, 2009 08:12 AM

3 comments, last by DevFred 15 years, 2 months ago

S8N

122

Author

February 14, 2009 08:12 AM

Hi, I've come across statements like this in other people's code several times but never really understood what exactly it was doing:

if (customer != null ? !customer.equals(order.customer) : order.customer != null)

(This is Java by the way) I understand that overall it's a boolean statement, and it's comprised of three other boolean statements. I think I understand generally what program state it is testing for, but what exactly are the question mark and colon symbols doing? I've only ever used symbols like || or && in my own boolean statements. Thanks! [smile]

http://www.thomaswiggins.co.uk (under construction)

Molle85

172

February 14, 2009 08:27 AM

can be translated to:

bool stuff;if( customer != null )   stuff = !customer.equals(order.customer);else   stuff = order.customer != null;if( stuff ){    // do stuff}

Promethium

580

February 14, 2009 08:29 AM

The "op1 ? op2 : op3" form is called the ternary operatory. In short it means "if op1 is true then return op2 else return op3". Read more about it here.

S8N

122

Author

February 14, 2009 08:36 AM

Ahh, okay. I understand. Thanks a lot guys! [smile]

http://www.thomaswiggins.co.uk (under construction)

DevFred

840

February 14, 2009 10:01 AM

Quiz time! What does the following program print?

Object x = (1 < 2) ? new Integer(1) : new Float(2);System.out.println(x);

a) 1
b) 2.0
c) throws an exception
d) none of the above

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>Java Puzzlers.

Quick question: What exactly does this line of code do?

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Quick question: What exactly does this line of code do?

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