how to make a non const copy of a const variable?

Code:

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const int a = 10;
int b;
b = const_cast <int> (a);

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I wonder why this isn`t working.

How to make a simple non const copy of a const variable?

Code:

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int b = a;

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You can't change consts. But all it takes to make a copy is reading the value, and of course you can do that.

No way?

I could write it to a file and then read it... But... You know....

No more elegant way?

Quote:

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Originally Posted by sept

No way?

I could write it to a file and then read it... But... You know....

No more elegant way?

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Who said anything about a file? You just need to copy it (read the value into a new variable). In other words, take out the const_cast and see what that does for you.

He means that you can't change consts.

About the only thing the const keyword does is prevent code from compiling when a const is used as an l-value.

Basically this means:

Code:

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const int a = 10;
// a = 20; won't compile
int b = a; // OK

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Not very complicated unfortunately.

My memory was that

Code:

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const int a = 5;
int b = a;

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brings a compile error can not convert from const int to int. But somehow I really messed up.
Solved, Thanks.

Const just means you can't change the original memory, but since you're making a copy of the given value at memory, it works fine.
Problem comes when passing pointers around. Since they all point to the original memory, you can't pass a const pointer where a normal pointer is expected.
Though it is possible to do away with const for such things as pointers. But they do put the implementation at risk, so do it with care.