Objective-C. NSArray, NSMutableArray

It's a collection of objects.

#import <Foundation/NSObject.h>
#import <Foundation/NSArray.h>
#import <Foundation/NSstring.h>
#import <Foundation/NSAutoreleasePool.h>


int main (int argc, const char * argv[]) 
{
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

    NSArray *months = [NSArray arrayWithObjects:
                       @"January", @"February", 
                       @"March", @"April", @"May", 
                       @"June", @"July", @"August",
                       @"September", @"October", @"November",
                       @"December", nil];
    
    NSLog(@"Month    Name");
    NSLog(@"-------------");
    
    int i;
    for (i = 0; i < [months count]; ++i)
    {
        NSLog(@"%2i. %@", i + 1, [months objectAtIndex: i]);
    }
    
    [pool drain];
    return 0;
}

There is also a mutable version of the array: NSMutableArray. The following program generates the prime numbers and store them in the array (because the number of the elements in the array is unknown in the beginning, NSMutableArray is used):

#import <Foundation/NSObject.h>
#import <Foundation/NSArray.h>
#import <Foundation/NSString.h>
#import <Foundation/NSAutoreleasePool.h>
#import <Foundation/NSValue.h>

#define MAX_PRIME 50

int main (int argc, const char * argv[]) 
{
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

    NSMutableArray* primes = [NSMutableArray arrayWithCapacity: 20];
    
    [primes addObject: [NSNumber numberWithInteger: 2]];
    [primes addObject: [NSNumber numberWithInteger: 3]];
    
    BOOL isPrime;
    int p, i, prevPrime;
    for (p = 5; p < MAX_PRIME; p += 2)
    {
        isPrime = YES;
        i = 1;
        do    {
            prevPrime = [[primes objectAtIndex: i] integerValue];
            if ( p % prevPrime == 0)
                isPrime = NO;
            
            ++i;
        } while (isPrime == YES && p / prevPrime >= prevPrime);
        
        if (isPrime)
            [primes addObject: [NSNumber numberWithInteger: p]];
    }
             
    for (i = 0; i < [primes count]; ++i)
             NSLog(@"%li", (long)[[primes objectAtIndex: i] integerValue]);
             
    
    [pool drain];
    return 0;
}