Converting NSString to Char Array

Question

I have an array full of NSString's in hex and what to create a char array from them. I'm not sure how this can be done.

So I have an array

NSArray *myArray = [NSArray arrayWithObjects:@"0xAA", @"0xBB", @"0xCC", nil];

from this I want to create a c char array, something similar to this

const unsigned char testing[] = { 0xAA, 0xBB, 0xCC };

Any advice would be appreciated

Thanks

sidyll · Accepted Answer · 2012-02-08 14:39:51Z

3

You can take the NSScaner approach:

NSArray *myArray =
    [NSArray arrayWithObjects:@"0xAA", @"0xBB", @"0xCC", nil];
int size = [myArray count];
unsigned char testing[size];

unsigned holder;

for (int i = 0; i < size; ++i) {
    [[NSScanner scannerWithString:[myArray objectAtIndex:i]]
                       scanHexInt:&holder];
    testing[i] = holder; /* or check for errors before assigning */
}

Or the C approach:

for (int i = 0; i < size; ++i) {
    sscanf([[myArray objectAtIndex:i] UTF8String], "%x", &holder);
    testing[i] = holder; /* same thing */
}

edited Feb 8, 2012 at 14:39

answered Feb 8, 2012 at 14:10

sidyll

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2 Comments

Malice Code Over a year ago

for the Obj-C approach, Xcode states that you can't initialize a parameter of type unsigned int* with value unsigned char* on the scanHexInt:testing+i line .... sorry new to C programming

sidyll Over a year ago

Oh, sure. Sorry, I just typed in the code without much thinking. I updated the answer with a safer way of doing it.

Jayyrus · Accepted Answer · 2012-02-08 14:07:31Z

3

using char testing[] you are defined an array of char. So just a string can be parsed into that array. You have to define

const unsigned char testing[][];

and in a loop fill it with this:

NSString *s = @"Some string";
const char *c = [s UTF8String];

answered Feb 8, 2012 at 14:07

Jayyrus

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