iOS Programming: The Big Nerd Ranch Guide

The Stack

There is another part of memory called the stack that is separate from the heap. The reason for the names heap and stack has to do with how we visualize them. The heap is a giant heaping mess of objects, and we use pointers to remember where those objects are stored within the heap. The stack, on the other hand, can be visualized as a physical stack of frames.

When a method (or function) is executed, it allocates a chunk of memory from the stack. This chunk of memory is called a frame, and it stores the values for variables declared inside the method. A variable declared inside a method is called a local variable.

When an application launches and runs the main function, the frame for main is put at the bottom of the stack. When