Z Language to Code, Formal Methods

1. FROM Z TO CODE

2. STEPWISE CONVERSION INTO
CODE
• 1. Transformations
• 2. Refinement
• 3. Code templates

3. TRANSFORMATIONS
Z schemas allow us to infer preconditions and post conditions.
Means value of elements before and after the initialization.

4. WHAT IS REFINEMENT?
Development often proceeds from an abstract specification to a detailed design.
This process is called refinement.

5. CODE TEMPLATES
Most specifications have schema which exhibit the same basic patterns. For example:
1. adding or removing elements in a list.
2. handling a sequence of events.
3. ordering a set of values

6. FROM Z TO CODE
Declarations
Tuple
State schemas

7. DECLARATIONS
IN Z
• | d1, d2:DICE
int i; int j = 10;
enum Traffic { Red, Yellow, Green};
IN
CODE(C++)

8. OPERATORS
• In z Language
• <,>,^,v
• =,-,/,+
• In programming
Language
• <.>.&,|
• =,-,/,+

9. TUPLE

10. IN Z
Struct employee
{
Int id;
String name;
string department;
}
IN CODE(C++)

11. STATE SCHEMAS
State schemas are usually implemented by data structures
whose contents can change frequently.
S = [x,y:Z]

12. STATE SCHEMAS
becomes this declaration for two program variables
int x,y; /* state schema S */
ALTERNATIVELY, A STATE SCHEMA CAN BE IMPLEMENTED BY THE DECLARATION OF A C++ STRUCTURE
Struct s
{
Int x,y;
}

13. ADVANTAGES OF USING Z
• A Z specification forces the engineer to completely analyze the problem domain. (e.g. identify
the state space and pre and post conditions for all operations).
• A Z specification forces all major design decisions to be made prior to coding the
implementation.
• Coding should not commence until you are certain about what you should be coding.
• A Z specification is a valuable tool for generating test data, and the conformance testing of
completed systems.

14. DISADVANTAGES OF Z LANGUAGE
• By using Z language more time require for completing a project rather than expected
time.
• It increase the cost of project.