How to set the validation for Full name field using Objective C?

Full name field validation using Objective C code.

if ([self validate:self.fullnamefield.text] == 0)

{

        NSLog(@"Please Enter Valid User Name");

}

- (BOOL)validate:(NSString *)string

{

    NSError *error             = NULL;

    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"[a-zA-Z .]" options:0 error:&error];

    

    NSUInteger numberOfMatches = [regex numberOfMatchesInString:string options:0 range:NSMakeRange(0, [string length])];

    

    return numberOfMatches == string.length;

}