IOS 开发之 NSMutableArray与NSArray 的区别

NSArray and its subclass NSMutableArray manage collections of objects called arrays.
 NSArray creates static arrays, and NSMutableArray creates dynamic arrays.

-
 (void)addObject:(id)anObject

Inherits from NSValue : NSObject

NSUInteger
 count = 1;

NSNumber
 *j = [NSNumber numberWithInt:count];

[ary
 addObject:j];

#pragma
 mark -

#pragma
 mark (NSMutableArray *)randArray:(NSMutableArray *)ary

-
 (NSMutableArray *)randArray:(NSMutableArray *)ary{

  NSMutableArray
 *tmpAry = [NSMutableArray arrayWithArray:ary];

  NSUInteger
 count = [ary count];

  for

(NSUInteger i = 0; i < count; ++i) {

    int

nElements = count - i;

    //
 Seed the random number generator

    srandom(time(NULL));

    int

n = (random() % nElements) + i;

    [tmpAry
 exchangeObjectAtIndex:i withObjectAtIndex:n];

  }

  return

tmpAry;

}