C scope question

Question

Is the following code valid

int main(){
int * a = 0;
if ( !a ) {
    int b[500];
    a = b;
}

//do something with a, 
//has the array a is 
//pointing too gone out
//of scope and garbage
//or is it still fine?
}

Answer 1

No it is not, b has gone out of scope, accessing it (through the pointer) is undefined behavior.