Some of the operations in standard programming languages can be modeled as actions

that change the state of the world. For example, the assignment operation changes the contents of a memory location, and the print operation changes the state of the output stream. A

program consisting of these operations can also be considered as a plan, whose goal is given

$436$ Chapter $11.$ Planning and Acting in the Real World

by the specification of the program. Therefore, planning algorithms can be used to construct

programs that achieve a given specification.

a$.$ Write an action schema for the assignment operator $($assigning the value of one variable

to another$).$ Remember that the original value will be overwritten!

b$.$ Show how object creation can be used by a planner to produce a plan for exchanging

the values of two variables by using a temporary variabl