Objective-C Fast Enumeration

Fast enumeration is the feature of Objective-C, helps in enumerating through a collection. Collections are the fundamental constructs. It is used to hold and manage the other objects. The main purpose of a collection is, it provides a common way to store and retrieve the object efficiently.

There are different types of collections in Objective-C. The most common collections in Objective-C are:

• NSSet
• NSDictionary
• NSArray
• NSMutableSet
• NSMutableDictionary
• NSMutableArray

Here is the general form to use fast enumeration in Objective-C:

for(classType variable in collectionObject )
{ 
  statements 
}

Objective-C Fast Enumeration Example

Here is an example program, illustrating fast enumeration in Objective-C:

/* Objective-C Fast Enumeration - Example Program */
		
#import <Foundation/Foundation.h>

int main()
{
   NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
   NSArray *array = [[NSArray alloc]
   initWithObjects:@"string1", @"string2",@"string3",nil];
   for(NSString *aString in array)
   {
      NSLog(@"Value = %@",aString);
   }
   [pool drain];
   
   return 0;
}

When we compile and execute the above program, it will produce the following output:

2014-10-15  06:26:22.835 demo[7426] Value = string1
2014-10-15 06:26:22.836 demo[7426] Value = string2
2014-10-15 06:26:22.836 demo[7426] Value = string3

Objective-C Online Test