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VI.4 Locations

Variables [Slide 185]

  • Static variables start with a lower case letter. Static variables are constant on any given interval.
  • State variables start with an uppercase letter. State variables change in value from state to state.

    The value of a state variable on an interval is defined to be its value on the first state. Thus, I=0 means I has initial value zero.

  • If V is a variable then so is next V.

Variables [Slide 186]

Variables and expressions may be of any of the following types:

0, 42, -97, etc.
true, false.
Lists may be of fixed or variable length.
String constants are of the form "abc".
Float constants are of the form $0.123$ or $0.123e+10$.
This is the type of predicates and functions.

The function type(X) returns a string representing the type of expression X. For example, type(9)="integer".

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