Objective C parse hex string to integer

Question

I would like to know how to parse a hex string, representing a number, in objective c. I am willing to use both an objective, or a C based method, either is fine.

example:

#01FFFFAB

should parse into the integer: 33554347

Any help would be appreciated!

Answer 1

you can use NSScanner for this

int outVal;
NSScanner* scanner = [NSScanner scannerWithString:@"0x01FFFFAB];
[scanner scanHexInt:&outVal];

outVal will contain the int you're looking for. The 0x is optional.

Answer 2

strtol() is your friend.

It converts a string to a long, and you can pass the base of the number in. Strip that # sign off first though, or pass to strtol a pointer to the first numerical character.

Answer 3

Joshua Weinberg's answer is mostly correct, however the Ox prefix is optional when scanning hexadecimal integers. If you have a string in the format #01FFFFAB, you can still use an NSScanner, but you can simply skip the first character.

unsigned result = 0;
NSScanner *scanner = [NSScanner scannerWithString:@"#01FFFFAB"];

[scanner setScanLocation:1]; // bypass '#' character
[scanner scanHexInt:&result];