Objective C 代码片段(类别)

 @interface NSString (reverse)

 -(NSString *) reverseString;

 @end

 @implementation NSString (reverse)

 -(NSString *) reverseString {
     int length = [self length];
     NSMutableString *reversedString;

     reversedString = [[NSMutableString alloc] initWithCapacity: length];

     while(length > ) {
         [reversedString appendString:[NSString stringWithFormat:@"%C", [self characterAtIndex:--length]]];
     }
     return [reversedString autorelease];
 }
  @end