How does it work?

Everytime you call a function:

• computer "remembers" where to come back;
  • address of next instruction is saved
• computer makes a copy of each argument passed by value
  • so that the function uses this copy
• starts executing the function
• any variables declared in the function are created

As you return from a function

• local variables are discarded
• computer goes back to where it was.
• example