Lab 4

What is the correct syntax to define a simple data type in VDM++?

• type MyType = seq of char;

• type MyType : seq of char;

• types MyType = seq of char;

• types MyType : seq of char;

Which of the following is an example of defining a union type in VDM++?

• Faculty = <FSKTM> | <FEB>;

• Faculty = <FSKTM, FEB>;

• Faculty : <FSKTM> | <FEB>;

• Faculty = {FSKTM, FEB};

Which of the following is NOT a valid predefined type in VDM++?

• nat

• char

• string

• real

In VDM++, how do you declare an instance variable of type int within a class?

• instance variable studentName : seq of char;

• instance variables studentName : seq of char;

• instance variable studentName : seq of char = "John Doe";

• instance variables studentName = "John Doe";

Which of the following is an example of an explicit function in VDM++?

• sum(a, b) == post RESULT = a + b;

• sum(a, b) == pre a > 0 and b > 0; post RESULT = a + b;

• sum(a, b);

• sum(a, b) == a + b;

Which of the following statements about implicit functions is true?

• Provide a full implementation of the computation.

• Used when you need to sequence operations.

• Use pre & post conditions to define expected behavior

• Cannot have any conditions.

What is the correct syntax to define an implicit function in VDM++?

• multiply(x, y) == post RESULT = x * y;

• multiply(x, y) ==> x * y;

• multiply(x, y) == x * y;

• multiply(x, y) == pre x > 0 and y > 0; post RESULT = x * y;

What is the main difference between a function and an operation in VDM++?

• Functions can have pre/postconditions, but operations cannot

• Functions change the system state, while operations do not

• Operations are used for mathematical calculations only

• Operations can change the system state, while functions cannot