casting a non-const variable to const.

[aliasghar25]

Hi everyone
I'll be grateful, if someone can help me.

Is there any way to cast a non-const variable to const one?

I want to read variable n from file and then use it to declare array "int arr[n]", but because n is non-const, the compiler doesn't allow me to do that.

[AdrianH]

You don't want to cast it to a const, you want it to BE a const. This cannot be done.

Use STL container std::vector instead. See http://www.cplusplus.com/reference/vector/vector/

[TheIdeasMan]

Array sizes have to be const and known at compile time, not run time.

Maybe you need a different container std::vector, std::list, std::map, std::set to name a few.

Here is a link to the tutorial on this site - check out he reference info & articles as well - all at the top left of this page.

http://www.cplusplus.com/doc/tutorial/typecasting/

HTH

[aliasghar25]

Thanks AdrianH...

[JLBorges]

> I want to read variable n from file and then use it to declare array "int arr[n]",
> but because n is non-const, the compiler doesn't allow me to do that.

See: http://www.mochima.com/tutorials/vectors.html

[aliasghar25]

to TheIdeasMan:
Thanks a lot...
but i think, when there is no need for dynamic memory allocation, working with array is much quicker than vector and so on...

however, thank you for your time :)

[Cubbi]

i think, when there is no need for dynamic memory allocation, working with array is much quicker than vector and so on

First of all, what makes you think so? And secondly, you actually have the need for dynamic memory allocation.