String won't url encode in iOS

Question

I'm seriously having a brain fart here, but I can't figure out why this isn't encoding for the life of me. Been searching all over, and I can't even get the code samples to encode. Any ideas?

NSString *searchString = @"waffl&es";

NSString *encodedSearchString = [searchString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSString *urlString = [NSString stringWithFormat:@"http://en.wikipedia.org/?search=%@", encodedSearchString];
NSURL *url = [NSURL URLWithString:urlString];

Answer 1

For future reference, this is what I found to work (i.e. encode everything properly)

+ (NSString*)encodeURL:(NSString *)string
{
    NSString *newString = (__bridge_transfer NSString *)CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault, (__bridge CFStringRef)string, NULL, CFSTR(":/?#[]@!$ &'()*+,;=\"<>%{}|\\^~`"), CFStringConvertNSStringEncodingToEncoding(NSUTF8StringEncoding));

    if (newString) 
    {
        return newString;
    }

    return @"";
}