Kingdom Hearts

The same chip of RAM may be used as stack memory when running one program and later used as heap memory when running some other program.

The difference is in how they are used.

Stack

Often a function or method calls another function which in turn calls another function etc.

The execution of all those functions remains suspended until the very last function returns its value.

All the information required to resume the execution of these functions is stored on the stack.

In particular, local variables are stored on the stack.

Local variables are often stored for short amounts of time while a function/method block uses them to compute a task.

Once a function/method has completed its cycle, the space on the stack used by all local variables is freed.

This chain of suspended function calls is the stack, because elements in the stack (function calls) depend on each other.

The stack is important to consider in exception handling and thread executions.

Heap

Heap

The heap is simply the memory used by programs to store global variables.

Element of the heap (variables) have no dependencies with each other and can always be accessed randomly at any time.

All global variables are stored in heap memory.

All variables dynamically created by the program with "new()" or "malloc()" or similar commands are also stored on the heap.

In some programming languages, all instances of an object, including all the attributes of that instance, are stored on the heap.

In those programming languages, local variables of a function that have object type are implemented as creating the new object on the heap,

and storing a reference to that object in the local variable, which is on the stack.

When that function exits, the heap memory used by each local variable that has object is freed, and then all the stack used by that stack is freed.

Comparison

A Heap reference is also stored in Stack memory until the life cycle of the object has completed. Inside the Heap reference all the the contents of the object are stored whereas with a local variable only the variable contents are stored in the stack.

Example:

Stack

var blue

var red

ref 0x456783 (Heap reference)

var tom

ref 0x498702 (Heap reference)

var diane

Heap (0x456783)

name => Susan

age => 26

city => London

height => 5'7

sex => female

Heap (0x498702)

name => Paul

age => 21

city => Glasgow

height => 6'0

sex => male

In addition to heap memory and stack memory, a completely separate section of memory stores the constructors and other methods of a class/object.

* Congo River - Marlow's journey on the Congo River can be said to represent a journey into one's inner spirit. As Marlow progresses further up the river in his search for Kurtz, he begins to learn more and more about himself. He comes to realize that he probably has more in common with the natives than the smug Europeans who have come to civilize them. At the end of his journey, Marlow learns that everyone has a dark side to them, but that some people can conceal it better than others.

* ivory - The ivory symbolizes greed and the destructive nature of man. The managers and agents of the Company are so obsessed with obtaining ivory that they forget about their morals and so-called civilized ways.

* white worsted - Marlow discovers the white worsted wrapped around a negro's neck at the Outer Station. The fabric can be said to represent the attempt of the Europeans to colonize the natives, and the strangling effect it has on them.

* Kurtz's painting - The painting at the Central Station is perhaps the most extensive symbol in the novel. The painting is of a blindfolded woman carrying a lighted torch, which distorts her face. The woman likely symbolizes the Europeans who have come to civilize the natives. The torch she carries represents the European customs and values that they try to force upon the native Africans. The woman is blindfolded because the Europeans cannot "see" the negative effects that their customs have on the natives. Her face has become distorted because, to the natives, the European customs seem rather repulsive.

* Eldorado Exploring Expedition - This group is symbolic of the Whites' search for something that cannot be attained. Eldorado is historically known as a city of gold that never actually existed. However, the prosperity that could possibly be gained was so overwhelming for this group that they felt compelled to risk their lives for it.

* candle on the steamship - Marlow brings a candle into Kurtz's quarters as Kurtz is dying on the ship. The candle is symbolic of Kurtz's losing struggle for life. When Kurtz finally submits to death, Marlow blows out the candle.

* General Manager - The manager symbolizes all the immorality of European colonization. It is no coincidence that he ran the most disorganized and deplorable station in the region. The manager led his station not through intelligence and acumen, but rather, through his ability to stay healthy and invoke uneasiness. He was not interested in actually colonizing the region. His only concern was to attain as much ivory as possible.

* Kurtz - Kurtz represents man's dark side and what can happen when it envelops you completely. Kurtz's prolonged exposure to the untamed regions of the Congo has removed all his ties to civilization. He no longer feels satisfied with just being a mere mortal, so instead transforms himself into an omnipotent being. Kurtz's descent into madness is firmly established with his disturbing final words, "The horror! The horror!"