Counter

The example describes a simple counter with the following capabilities:

The counter provides capability to reset its value to zero;
The counter has capability to increment its value by one;
The counter has capability to display its current value.

The counter is the system under development in the MSC specification. The name of the system is 'Counter'. External entity accessing the variable is named 'User'.

The following three scenarios are present in the specification:


Scenario	Description	MSC diagram	Interaction
Reset	set the value of the counter to zero	Counter_Reset	The user sends a message 'S_Reset' to the counter
Incr	increment the value of the counter by one	Counter_Incr	The user sends a message 'Incr' to the counter
Display	obtain the value of the counter	Counter_Display	The user sends a message 'Display' to the counter. The counter returns its value with a message 'Show'.

MSC Counter_Init specifies the initialization of the counter. At the condition 'a_loop' the choice between three use cases is made. The behavior specified by this model is represented by HMSC 'Counter'.

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