iphone nscanner issue

Question

It seems nsscanner cant do her job, when it scans a dynamically inputting string. Let me first write my codes:

NSString *setext = mySearchBar.text;
NSScanner *scanner = [NSScanner scannerWithString:setext];
NSString *a = @"a";
NSString *aa;
[scanner scanUpToString:a intoString:NULL];
while ([scanner isAtEnd] == NO)
{
    if ( [scanner scanString:a intoString:NULL]);   
    {
        NSLog (@" scan: %@ ", aa);      
    }
}

I have tried these codes in many of methods, but I get same result: the simulator terminated itself without any crash logs, when I write something in the searchbar. mySearchBar is added programmatically and is of UISearchBar class and is linked to self.

When I tried to rewrite setext to searchText in filterContent method for searching and comparing, NSLog shows endless amount of either

• "scan : MainViewController"

or

• "scan: (first character I entered)"

and then crashed. MainViewController is of UIViewController class.

I have tried these codes from Apple Documentation;

http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/Strings/Articles/Scanners.html :

NSString *string = @"Product: Acme Potato Peeler; Cost: 0.98 73\n\
    Product: Chef Pierre Pasta Fork; Cost: 0.75 19\n\
    Product: Chef Pierre Colander; Cost: 1.27 2\n";

    NSCharacterSet *semicolonSet;
    NSScanner *theScanner;

    NSString *PRODUCT = @"Product:";
    NSString *COST = @"Cost:";

    NSString *productName;
    float productCost;
    NSInteger productSold;

    semicolonSet = [NSCharacterSet characterSetWithCharactersInString:@";"];
    theScanner = [NSScanner scannerWithString:string];

    while ([theScanner isAtEnd] == NO)
    {
        if ([theScanner scanString:PRODUCT intoString:NULL] &&
            [theScanner scanUpToCharactersFromSet:semicolonSet
                                       intoString:&productName] &&
            [theScanner scanString:@";" intoString:NULL] &&
            [theScanner scanString:COST intoString:NULL] &&
            [theScanner scanFloat:&productCost] &&
            [theScanner scanInteger:&productSold])
        {
            NSLog(@"Sales of %@: $%1.2f", productName, productCost * productSold);
        }
    }

and it works perfectly in any method. NSLog of this code showed up once and is perfectly written. But I cant see why this code works, not mine.

My goal is to detect special characters in the searchbar. If text in the searchbar contains such character(s), so I can disable NSDiactricInsensitiveSearch in NSComparisonResult. Then the search results will display words containing special characters which arent part of diactric characters.

---

EDIT 16 august:

Ok, here are my codes for nscomparisonresult. @JohnBrighton:`s solution works, but nslog came in a for loop and I couldnt click on anything on the app for the first character I enter... If I paste these codes before for loop, then searching doesnt work;

for (mystr in noWords) {
        NSComparisonResult result;
        NSString *string = mySearchBar.text;
        NSRange range = [string rangeOfString:@"ø"];
        if (range.location != NSNotFound) {
            result = [mystr compare:searchText options:(NSCaseInsensitiveSearch) 
                range:NSMakeRange(0, [searchText length])];     
            NSLog (@" detected");
        }   
        else 
            {
                result = [mystr compare:searchText  options:(NSCaseInsensitiveSearch|NSDiacriticInsensitiveSearch) 
                              range:NSMakeRange(0, [searchText length])];
            NSLog(@"normal");
        }   
    if (result == NSOrderedSame)
        {
        [self.filteredListContent addObject:mystr];
        }
    }

---

EDIT 17 august, rewrited the codes above, so the whole method is visible:

- (void)filterContentForSearchText:(NSString*)searchText 
{

    for (mystr in noWords) 
     {

        clock_t start = clock(), end;       

        NSComparisonResult result;
        NSString *string = searchText;
        NSRange range = [string rangeOfString:@"æ"];
        NSRange range2 = [string rangeOfString:@"ø"];
        NSRange range3 = [string rangeOfString:@"å"];
        if (range.location != NSNotFound||range2.location != NSNotFound ||range3.location != NSNotFound ) {
            // This means the character has been found.
            // The position is at range.location.

            result = [mystr compare:searchText options:(NSCaseInsensitiveSearch) 
                              range:NSMakeRange(0, [searchText length])];       
        }   
        else {
            result = [mystr compare:searchText options:(NSCaseInsensitiveSearch|NSDiacriticInsensitiveSearch) 
                              range:NSMakeRange(0, [searchText length])];
        }

        end = clock();
        end = ((double)end - start) / CLOCKS_PER_SEC;
        printf("Time taken: %f \n", (double)end);            

    if (result == NSOrderedSame)
        {
        [self.filteredListContent addObject:mystr];
        }
    }   
}

It came up with endless amount of NSLogs showing "Time taken: 0" instead of "Time taken: 0.0000" from your previous code.

Answer 1

You are trying to print out "aa", which is something you don't want since you just declared it. Initialize it/print something else out, and it'll work.

Edit: here's a good way to detect if |string| contains "!".

NSString *string = @"it works!";
NSRange range = [string rangeOfString:@"!"];
if (range.location != NSNotFound) {
    /* This means the character has been found.
       The position is at range.location. */
}

Edit #2: here's a way to measure the execution time.

#include <time.h>
...
clock_t start = clock(), end;
...[do your tasks]...
end = clock();
end = ((double)end - start) / CLOCKS_PER_SEC;
printf("Time taken: %f\n", end);