all tasks

Task/Sort-using-a-custom-comparator/Objective-C/sort-using-a-custom-comparator-1.m

@@ -0,0 +1,28 @@
+#import <Foundation/Foundation.h>
+
+#define esign(X) (((X)>0)?1:(((X)<0)?-1:0))
+
+int main()
+{
+  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
+
+  NSMutableArray *arr =
+  [NSMutableArray
+    arrayWithArray: [@"this is a set of strings to sort"
+                     componentsSeparatedByString: @" "]
+   ];
+
+  [arr sortUsingComparator: ^NSComparisonResult(id obj1, id obj2){
+    NSComparisonResult l = esign((int)([obj1 length] - [obj2 length]));
+    return l ? -l // reverse the ordering
+             : [obj1 caseInsensitiveCompare: obj2];
+   }];
+
+  for( NSString *str in arr )
+  {
+    NSLog(@"%@", str);
+  }
+
+  [pool release];
+  return EXIT_SUCCESS;
+}

Task/Sort-using-a-custom-comparator/Objective-C/sort-using-a-custom-comparator-2.m

@@ -0,0 +1,38 @@
+#import <Foundation/Foundation.h>
+
+@interface NSString (CustomComp)
+- (NSComparisonResult)my_compare: (id)obj;
+@end
+
+#define esign(X) (((X)>0)?1:(((X)<0)?-1:0))
+@implementation NSString (CustomComp)
+- (NSComparisonResult)my_compare: (id)obj
+{
+  NSComparisonResult l = esign((int)([self length] - [obj length]));
+  return l ? -l // reverse the ordering
+           : [self caseInsensitiveCompare: obj];
+}
+@end
+
+int main()
+{
+  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
+
+  NSMutableArray *arr =
+     [NSMutableArray
+       arrayWithArray: [@"this is a set of strings to sort"
+                         componentsSeparatedByString: @" "]
+     ];
+
+  [arr sortUsingSelector: @selector(my_compare:)];
+
+  NSEnumerator *iter = [arr objectEnumerator];
+  NSString *str;
+  while( (str = [iter nextObject]) != nil )
+  {
+    NSLog(@"%@", str);
+  }
+
+  [pool release];
+  return EXIT_SUCCESS;
+}

Task/Sort-using-a-custom-comparator/Objective-C/sort-using-a-custom-comparator-3.m

@@ -0,0 +1,22 @@
+#import <Foundation/Foundation.h>
+
+int main()
+{
+  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
+
+  NSArray *strings = [@"Here are some sample strings to be sorted" componentsSeparatedByString:@" "];
+
+  NSSortDescriptor *sd1 = [[NSSortDescriptor alloc] initWithKey:@"length" ascending:NO];
+  NSSortDescriptor *sd2 = [[NSSortDescriptor alloc] initWithKey:@"lowercaseString" ascending:YES];
+
+  NSArray *sortDescriptors = [NSArray arrayWithObjects:sd1, sd2, nil];
+  [sd1 release];
+  [sd2 release];
+
+  NSArray *sorted = [strings sortedArrayUsingDescriptors:sortDescriptors];
+  NSLog(@"%@", sorted);
+
+  [pool release];
+
+  return 0;
+}