Regarding Pointer

Hi Friends,

Can we initialize a non-zero value to a pointer variable?

Ex : int *p=10;


Thanks in Advance!!!!

Sort of. You can do that, and it will make the pointer point to the memory address 10, which you don't own; thereafter, any attempt to use the pointer will result in disaster (unless you first make it point to somewhere "real").

Thanks Friend!!!

Also I want to know 2 more things..

Can i declare like this:

1) int *p = 0; // I guess p here would be a NULL pointer.

2) int *p, q;
p = &q;
p=4; // What will p contain?Is it a valid statement?

Thanks in Advance!!!!

Quote:

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Originally Posted by tabstop

Sort of. You can do that, and it will make the pointer point to the memory address 10

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Sorry, but no. You can't implicitly convert int to int*. You have to make an explicit conversion:

Code:

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int* p = (int*)10;

or

int* p = reinterpret_cast<int*>(10);

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but you can do:

Code:

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int* p = new int(10);

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But this is a different matter.

0 (zero) is the only literal constant allowed to be assigned to a pointer type.

Quote:

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p=4; // What will p contain?Is it a valid statement?

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Again you are trying to assign an integer to a pointer. p is a pointer, q is an integer (but avoid declaring a mixture of pointers and other types on a single line), so the first two lines are fine.

What you can do is:

Code:

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*p = 4;

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This means, set the value of the int that p points to (in this case q) equal to 4.