Using name space and scope

http://stackoverflow.com/questions/223021/whats-the-scope-of-the-using-declaration-in-c

The scope of the using statement depends on where it is located in the code:

• Placed at the top of a file, it has scope throughout that file.
• If this is a header file, it will have scope in all files that include that header. In general, this is "not a good idea" as it can have unexpected side effects
• Otherwise the using statement has scope within the block that contains it from the point it occurs to the end of the block. If it is placed within a method, it will have scope within that method. If it is placed within a class definition it will have scope within that class.

http://stackoverflow.com/questions/1677778/why-enclose-blocks-of-c-code-in-curly-braces

http://stackoverflow.com/questions/2759371/in-c-do-braces-act-as-a-stack-frame

void foo(int[]);
void bar(void);
void foobar(int); 

void foobar(int flag) {
    if (flag) {
        int big[100000000];
        foo(big);
    }
    bar();
}

gives:

_foobar:
    pushl   %ebp
    movl    %esp, %ebp
    movl    $400000008, %eax
    call    __alloca
    cmpl    $0, 8(%ebp)
    je      L2
    leal    -400000000(%ebp), %eax
    movl    %eax, (%esp)
    call    _foo
L2:
    call    _bar
    leave
    ret