disable a variable?

[ppolcz]

Hello all!
How can I disable a variable, or change it's type;
eg:
//...
int variable
//using it
//disable it
char variable
//using it as a charecter

If you can help, thanks in advence!

[Bazzy]

scope:

//...
{
    int variable
    //using it
}  //disable it

char variable
//using it as a charecter