Standard ML Programming/Examples and Exercises

Values and Functions

• Indicate the identifiers, keywords, and special constants in the following piece of code. What is the value of the second a?

 val a = 5
 val b = 9
 val a = 2*a+b;

• Construct a tuple with 4 positions and 3 components.

• What is the type of t?

 fun f a = 2
 val t = (true,f,f 1);

• Write a function that returns the value 2 for the arguments 0, 1 and 2 and returns 3 for all other arguments.

• Write a function that returns -1 for all negative and +1 for all positive arguments and 0 for the argument 0.

• Create a function min(a:int,b:int) that returns the smaller one of its 2 arguments. Do the separation of the argument values in 3 different ways. Using a Cartesian argument-pattern, using a projection and using a local declaration.

(solutions to this chapter are here)

Recursion

• Create a function power9(x) that calculates the 9th power of x. Preferably using as few multiplications as possible.

• Calculate the greatest common denominator from 2 positive integer arguments.

• Calculate mul(n,z)=n*z without using the * operator for $n\in \mathbb {N}$ and $z\in \mathbb {Z}$

• Calculate power2(n) by only using addition and resursion. (hint: it is possible to rewrite the square function as a summation of natural numbers.)

(solutions to this chapter are here)