A demonstration of using closures in Objective C. In Objective C terminology, it's called 'Blocks' instead of closures. Here I'm creating a 'block' that can create other 'blocks' by supplying a parameter. I run this in XCode 4.6 and Mac OS X 10.8. I had ARC turned on while I was coding this, but I think it's not a must for this particular exampl…

objc-blocks.mm

#import <Cocoa/Cocoa.h>

int main(int argc, char *argv[])
{
    int (^(^makeAdder)(int))(int) = ^(int toAdd) {
        int (^fn)(int) = ^(int arg) {
            return toAdd + arg;
        };
        return fn;
    };
    
    int (^tenAdder)(int) = makeAdder(10);
    int (^twentyAdder)(int) = makeAdder(20);

    int arg = 3;
    
    NSLog(@"Using tenAdder() with arg %d -> result : %d", arg, tenAdder(arg));
    NSLog(@"Using twentyAdder() with arg %d -> result : %d", arg, twentyAdder(arg));

}