a.m

// clang -Wall -x objective-c -std=c99 -fobjc-arc -framework Foundation -o a.out a.m
#import <objc/objc.h>
#import <objc/objc-runtime.h>
#import <CoreFoundation/CoreFoundation.h>
#import <Foundation/Foundation.h>

void foo(int a)
{
    switch (a)
    {
    case 1: {
        int b = a + 1;
        NSLog(@"a: %d, b: %d", a, b);
        break;
    }
    case 3: {
        int b = a + 2;
        NSLog(@"a: %d, b: %d", a, b);
        break;
    }
    default: {
        int b = a + 3;
        NSLog(@"a: %d, b: %d", a, b);
        break;
    }
    }
}

int main()
{
    @autoreleasepool {
        for (int i = 0; i < 10; ++i)
        {
            foo(i);
        }
    }
}