Question

Possible Duplicate:
const in C vs const in C++

I have following code

In C

int main()
{
    const int k;//allowed but garbage and later we can't modify
    printf("%d",k);
}

o/p=Garbage

In C++

int main()
{
    const int k; //not allowed from here itself
    printf("%d",k);
}

o/p-compile time error

I having doubt what is the use of the const in C if it it is allowed to declare it with out initialization but after it declaration we can’t initialize it.

But is c++ it is good that we can’t declare a const value without initialization.

Is there any use of the variable k in C or it is useless,if we only declare it as later modification is not possible.

Answer 1

It has no use by itself.

However, there are compiler specific extensions where this becomes useful again.
C Compilers for embedded platforms, for example, often have extensions that allow to give a variable a fixed address, or as an alias for an memory mapped I/O port.

The const would indicate / enforce that you only read from that address, for example a memory mapped input port.