ivar namespacing in objc

main.m

#import <Foundation/Foundation.h>

@interface Foo : NSObject
@end
@implementation Foo {
    int _foo;
}
- (id)init
{
    _foo = 1;
    return self;
}
- (int)foo1
{
    return _foo;
}
@end

@interface Bar : Foo
@end
@implementation Bar {
    int _foo;
}
- (id)init
{
    [super init];
    _foo = 2;
    return self;
}
- (int)foo2
{
    return _foo;
}
@end

int main(int argc, const char * argv[])
{

    @autoreleasepool {
        Bar *foo = [[Bar new] autorelease];
        // insert code here...
        NSLog(@"Hello, World! %d %d", [foo foo1], [foo foo2]);
        
    }
    return 0;
}