Objective-C Variable Declaration Confusion

Question

I am confused as to why I am allowed to do this (the if statement is to just show scope):

int i = 0;
if(true)
{
    float i = 1.1;
}

I have a c# background and something like this is not allowed. Basically, the programmer is redeclaring the variable 'i', thus giving 'i' a new meaning. Any insight would be appreciated.

Thanks!

Answer 1

In C (and by extension, in Objective C) it is allowed to declare local variables in the inner scope that would hide variables of the outer scope. You can get rid of if and write this:

int i = 0;
{
    // Here, the outer i becomes inaccessible
    float i = 1.1;
    {
        int i = 2;
        printf("%d", i); // 2 is printed
    }
}

demo

C# standard decided against that, probably because it has a high probability of being an error, but C/Objective C does not have a problem with it.

Answer 2

Turn on "Hidden local variables" in your build settings to get a warning.