How can i use id as a temporary storage for a variable value - iphone

Question

I am new to programming so can anyone here please let me know if the below is the valid in Objective-C.
Thanks.
#interface MainViewController : UIViewController
{
id iTempStore;
}
#property (nonatomic, assign) id iTempStore;
// FirstViewController
#interface FirstViewController : UIViewController
{
MainViewController* pParent;
}
-(void) SomeFunction
{
m_pParent = [[[MainViewController]alloc]init];
NSString* pTest = [[[NSString alloc] initWithString:#"Test"]autorelease];
// Is this valid way to store an object ???
[m_pParent setITempStore: pTest];
// Check Value
NSString* pValue = [m_pParent iTempStore];
NSLog(#"Value is: %#", pValue);// Value is: Test
[m_pParent release];
}

Answer 1

id can hold a reference to any object, so storing a string there is fine, but since you are backing with an iVar you probably want to use copy or retain rather than assign as your propery storage class... you would use copy if it were alway NSString or any class that has a mutable subclass... but since id can't specify that to be type safe you would either do :
#property(copy) id <NSCopying> iTempStore;
or
#propery(retain) id iTempStore;

Answer 2

it's technically ok...but not very...good
If you're declaring a property you don't necessary need it as instance variable too.
Do not use non-ARC things ...ARC is supported on all ios devices ( not sure about first gen) but on all that really matter at least.
If you know the object type you don't need to use id. id is used for when you are not sure of the returning type.
your code should look something like this :
#interface MainViewController : UIViewController
#property (nonatomic, assign) NSString* iTempStore;
// FirstViewController
#interface FirstViewController : UIViewController
{
MainViewController* pParent;
}
-(void) SomeFunction
{
m_pParent = [[MainViewController alloc]init];
NSString* pTest = [[[NSString stringWithString:#"Test"];
[m_pParent setITempStore: pTest];
NSString* pValue = [m_pParent iTempStore];
NSLog(#"Value is: %#", pValue);
}