Char Pointer address assigned to address of integer pointer

Question

I'm trying to do something very simple, at least I thought, with no success. I would like to assign the address pointed to by an integer pointer to the address pointed to by a char pointer. Example

//C++

int *pointerint;
char *pointerchar;
pointerchar = pointerint;

//

I've tried to do this severals different ways without success.

Example:

pointerchar = (char *) &pointerint;

The compiler excepts it but the address assigned to the pointer is zero. That can not be correct. Can anyone tell me how to do this correctly and what I am doing wrong. Thanks in advance for all your help.

This is indeed very simple to do as you can see from the answers ... but why do you want to do it? It's a generally dangerous operation, especially in the hands a rookie. — Jim Balter
– Jim Balter, Commented Sep 26, 2012 at 19:10

ouah · Accepted Answer · 2012-09-26 19:06:14Z

3

Try (if C):

pointerchar = (char *) pointerint;

answered Sep 26, 2012 at 19:06

ouah

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15 Comments

slugonamission Over a year ago

This is correct, but to extend, what you did there is typecasted the address of the pointer. Since pointerint is already a pointer, you don't need to use the & operator again.

ouah Over a year ago

Here I convert the value of the pointer and not the address of the pointer (what the OP did).

ouah Over a year ago

@LuchianGrigore I assume he initializes the pointerint pointer.

slugonamission Over a year ago

Even if pointerint isn't initialised, it will work. You'd just be copying the number across. All you're changing is the semantic meaning of the data that is pointed to.

ouah Over a year ago

@slugonamission a non-initialized pointer is an invalid pointer and accessing (even just reading it) an invalid pointer is undefined behavior.

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Luchian Grigore · Accepted Answer · 2012-09-26 19:08:31Z

3

Now that you have a C answer, here's a C++ one:

int *pointerint;  
char *pointerchar;
//initialize pointerint
pointerchar = reinterpret_cast<char*>(pointerint);

Note that if you don't initialize the pointerint, you'll run into undefined behavior.

answered Sep 26, 2012 at 19:08

Luchian Grigore

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4 Comments

Jim Balter Over a year ago

pointers? You mean "if you don't initialize pointerint" ... you just set pointerchar and don't need to initialize it.

Luchian Grigore Over a year ago

@JimBalter true. That's what I meant. :)

Hindol Over a year ago

I always love C++ answers, :) +1

user1701238 Over a year ago

Yes that's the correct answer, this holds true for C as well, initializing the pointer is key! Also, I need to subtract 3 for the final pointer to start the char pointer at the MSB in the word, byte 0.

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