Is there some ninja trick to make a variable constant after its declaration?

Question

I know the answer is 99.99% no, but I figured it was worth a try, you never know.

void SomeFunction(int a)
{
    // Here some processing happens on a, for ex         


        

Answer 1

I don't actually suggest doing this, but you could use creative variable shadowing to simulate something like what you want:

void SomeFunction(int a)
{
    // Here some processing happens on a, for example:
    a *= 50;
    a %= 10;
    if(example())
       a = 0;
    {
        const int b = a;
        const int a = b;  // New a, shadows the outside one.
        // Do whatever you want inside these nested braces, "a" is now const.
    }
}

Answer 2

Answers were pretty solid, but honestly I can't really think of a GOOD situation to use this in. However in the event you want to Pre-Calculate a constant which is basically what you are doing you have a few main ways You can do this.

First we can do the following. So the compiler will simply set CompileA# for us in this case it's 50, 100, and 150.

const int CompileA1 = EarlyCalc(1);
const int CompileA2 = EarlyCalc(2);
const int CompileA3 = EarlyCalc(3);

int EarlyCalc(int a)
{
    a *= 50;
    return a;
}

Now anything beyond that there's so many ways you can handle this. I liked the suggestion as someone else had mentioned of doing.

void SomeFunc(int a)
{
    const int A = EarlyCalc(a);
    //We Can't edit A.
}

But another way could be...

SomeFunc(EarlcCalc(a));

void SomeFunc(const int A)
{
    //We can't edit A.
}

Or even..

SomeFunction(int a)
{
    a *= 50;
    ActualFunction(a);
}

void ActualFunction(const int A)
{
    //We can't edit A.
}