using new

How can a C++ developer use the placement new syntax to make new allocate an object of class SomeClass at a particular memory address stored in a pointer type variable named pmem?

A. new SomeClass(pmem);
B. new(pmem) SomeClass;
C. new SomeClass pmem;
D. new pmem SomeClass;
E. new (pmem, SomeClass);

Hmm. This confuses me a bit as I'm only use to seeing:

Code:

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someClass *pmem = new someClass;

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But I'm rather sure A is correct as its a copy constructor. And the rest are incorrect.

Can anyone confirm. Thx.

B is correct and the others are not. You are apparently unfamiliar with placement new.

Where did you get this question from? The word "allocate" is rather dangerous in this context since placement new is not used to allocate memory. Does your book mention anything on placement new? If not, you might want to search the web on "placement new".

Quote:

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Originally Posted by CornedBee

You are apparently unfamiliar with placement new.

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I'm use to using malloc instead.

Quote:

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Originally Posted by laserlight

Where did you get this question from?

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http://ikmnet.com/

Quote:

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Originally Posted by laserlight

Does your book mention anything on placement new?

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Nope :( - was not aware of "placement new" until now.

malloc and placement new have absolutely nothing to do with each other. In fact, they're pretty much orthogonal: malloc allocates memory, placement new constructs an object inside.

Quote:

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Originally Posted by CornedBee

malloc and placement new have absolutely nothing to do with each other. In fact, they're pretty much orthogonal: malloc allocates memory, placement new constructs an object inside.

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Just found that out now. Thx peoplez.

Quote:

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Originally Posted by coletek

http://ikmnet.com/

Nope :( - was not aware of "placement new" until now.

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So does that mean we're answering questions to help you get hired for a job you're not qualified for?

Written tests are given to determine job eligibility? How offensive. Aren't there degrees for that?

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Originally Posted by CodeMonkey

Written tests are given to determine job eligibility? How offensive. Aren't there degrees for that?

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Degrees don't tell you much other than you spent a lot of money for a fancy piece of paper. The real question is, did you learn anything when you were taking all those courses, or did you just cheat your way through...