ios method to insert spaces in string - iphone

Question

In my app I download a file from amazon's s3, which does not work unless the file name has no spaces in it. For example, one of the files is "HoleByNature". I would like to display this to the user as "Hole By Nature", even though the file name will still have no spaces in it.
I was thinking of writing a method to search through the string starting at the 1st character (not the 0th) and every time I find a capital letter I create a new string with a substring until that index with a space and a substring until the rest.
So I have two questions.
If I use NSString's characterAtIndex, how do I know if that character is capital or not?
Is there a better way to do this?
Thank you!

Answer 1

Works for all unicode uppercase and titlecase letters
- (NSString*) spaceUppercase:(NSString*) text {
NSCharacterSet *set = [NSCharacterSet uppercaseLetterCharacterSet];
NSMutableString *result = [NSMutableString new];
for (int i = 0; i < [text length]; i++) {
unichar c = [text characterAtIndex:i];
if ([set characterIsMember:c] && i!=0){
[result appendFormat:#" %C",c];
} else {
[result appendFormat:#"%C",c];
}
}
return result;
}

Answer 2

I would not go to that approach because I know you can download files with spaces try this please when you construct the NSUrl object
#"my_web_site_url\sub_domain\sub_folder\My%20File.txt
this will download "My File.txt" from the URL provided. so basically you can replace all spaces in the URL with %20
reference:
http://www.w3schools.com/tags/ref_urlencode.asp

Answer 3

Got it working with Jano's answer but using the isupper function as suggested by Richard J. Ross III.
- (NSString*) spaceUppercase:(NSString*) text
{
NSMutableString *result = [NSMutableString new];
[result appendFormat:#"%C",[text characterAtIndex:0]];
for (int i = 1; i < [text length]; i++)
{
unichar c = [text characterAtIndex:i];
if (isupper(c))
{
[result appendFormat:#" %C",c];
}
else
{
[result appendFormat:#"%C",c];
}
}
return result;
}