class and object

calling method:

ex:

[test run];

test is a object, run is its method

calling method with arguments:

ex:

[test run:1  secondArg:2];

1 is first argument,  2 is second argument, secondArg: is the description of second argument

create a object:

test = [NSMutableArray alloc];

create & init a object:

test = [  [NSMutableArray alloc] init];