Question

I am obtaining the mac(hw) address of an interface using CWNetwork. Now OS X gives me this mac address in the xx:xx:xx:xx:xx:xx format. But if the first digit is 0, OS X will output the address as 4:aa:dd:ee:34:40, instead of 04:aa:dd:ee:34:40.

Now I am trying to take this string 4:aa:dd:ee:34:40 and convert it to 04:aa:dd:ee:34:40 before displaying it.
Any ideas ? APpreciate the help.

Answer 1

I believe the following code does what you want.

NSString *macAddress = @"4:aa:dd:ee:34:40";
NSScanner *scanner = [NSScanner scannerWithString:macAddress];
[scanner setCharactersToBeSkipped:[NSCharacterSet punctuationCharacterSet]];
NSMutableString *result = [NSMutableString stringWithCapacity:[macAddress length]];
while (![scanner isAtEnd]) {
    unsigned theValue;
    if ([scanner scanHexInt:&theValue]) {
        [result appendFormat:@":%02x",theValue];
    } else {
        [result appendString:@":??"];
    }
}
NSLog(@"%@",[result substringFromIndex:1]);