NSMutablearray starts printing from last element instead of first - ios

Question

I´m using this method to initialize an nsmutablearray
- (void)getAllContacts
{
Contact *contact = [[Contact alloc] init];
self.allContacts = [[NSMutableArray alloc] init];
int i=0;
for (i=0; i<5; i++)
{
contact.nome = [[NSString alloc] initWithFormat:#"Bruno %d", i];
[self.allContacts insertObject:contact atIndex:i];
}
}
Pretty straightforward! But right after, i do a for to print it´s elements like:
for (int i=0; i<[self.allContacts count]; i++)
{
Contact *c = [self.allContacts objectAtIndex:i];
NSLog(#"i=%d\nNome:%#", i, c.nome);
}
And it will show me 5 times the last element "Bruno 4". It doesn´t start from 0 and increments. What should i do to start from 0?

Answer 1

Try this:
- (void)getAllContacts
{
Contact *contact = nil;
self.allContacts = [NSMutableArray array];
int i=0;
for (i=0; i<5; i++)
{
contact = [Contact new];
contact.nome = [NSString stringWithFormat:#"Bruno %d", i];
[self.allContacts addObject:contact];
[contact release]
}
}
and please take a look at: Memoy Management

Answer 2

Because you are inserting the same object 5 times into the array. You need to create a new Contact object at every execution of the for loop.

Answer 3

What you are doing is you're actually adding one instance of the Contact class 5 times in the array and only changing nome property. Here is the correct way to do this:
- (void)getAllContacts
{
//alloc init returns a retained object and self.allContacts calls the setter, which additionally retains it.
self.allContacts = [[[NSMutableArray alloc] init] autorelease];
int i=0;
for (i=0; i<5; i++)
{
//Create the Contact object
Contact *contact = [[Contact alloc] init];
//Set the nome property
contact.nome = [NSString stringWithFormat:#"Bruno %d", i];
//Add the instance to the array
[self.allContacts addObject:contact];
//Release the instance because the array retains it and you're not responsible for its memory management anymore.
[contact release];
}
}