NSComparisonResult and NSComparator - what are they?

Question

What is NSComparisonResult and NSComparator?

I\'ve seen one of the type definitions, something like that:

typedef NSComparisonR         


        

Answer 1

NSComparisonResult comparisionresult;
NSString * alphabet1;
NSString * alphabet2;


// Case 1

alphabet1 = @"a";
alphabet2 = @"A";
comparisionresult = [alphabet1 caseInsensitiveCompare:alphabet2];

if (comparisionresult == NSOrderedSame)
    NSLog(@"a and a are same. And the NSComparisionResult Value is %ld \n\n", comparisionresult);
//Result: a and a are same. And the NSComparisionResult Value is 0

// Case 2
alphabet1 = @"a";
alphabet2 = @"B";
comparisionresult = [alphabet1 caseInsensitiveCompare:alphabet2];

if (comparisionresult == NSOrderedAscending)
    NSLog(@"a is greater than b. And the NSComparisionResult Value is %ld \n\n", comparisionresult);
//Result: a is greater than b. And the NSComparisionResult Value is -1

// Case 3
alphabet1 = @"B";
alphabet2 = @"a";
comparisionresult = [alphabet1 caseInsensitiveCompare:alphabet2];

if (comparisionresult == NSOrderedDescending)
    NSLog(@"b is less than a. And the NSComparisionResult Value is %ld", comparisionresult);

//Result: b is less than a. And the NSComparisionResult Value is 1