//NSNumber Creation
NSNumber *value;
value = [NSNumber numberWithChar:'X'];
value = [NSNumber numberWithInt:12345];
value = [NSNumber numberWithUnsignedLong:12345ul];
value = [NSNumber numberWithLongLong:12345ll];
value = [NSNumber numberWithFloat:123.45f];
value = [NSNumber numberWithDouble:123.45];
value = [NSNumber numberWithBool:YES];

//NSNumber Literals
NSNumber *value;
value = @'X';
value = @12345;
value = @12345ul;
value = @12345ll;
value = @123.45f;
value = @123.45;
value = @YES;

NSMutableArray *mArr = [NSMutableArray arrayWithObjects:
    v1, [NSNumber numberWithUnsignedInt:255u],
nil];
[mArr replaceObjectAtIndex:1 withObject:[NSNumber numberWithChar:'z']];

NSMutableArray *mArr = [@[v1, @255U] mutableCopy];
// array/dict literals are immutable so we need a mutable copy
ict literals are immutable so we need a mutable copy
mArr[1] = @'z';

NSMutableDictionary *mDict = [NSMutableDictionary
    dictionaryWithObjectAndKeys:[NSString stringWithUTF8String:"Hello", k1,
                                [NSString stringWithUTF8String:"World"],k2,
nil];
[mDict setObject:[NSString stringWithUTF8String:"Ciao" forKey:k1]];

NSMutableDictionary *mDict = [ @{
    @"key1" : @"Hello",
    @"key2" : @"World"
} mutableCopy];
mDict[@"key1"] = "@Ciao";