CSC 270
Homework 1

C, C++, or Java version:

(This is a good exercise to try in each language.)

Write a program that reads in three double numbers, prints their sum and average (appropriately labelled), and prints out how many of them are positive.  For example, if the input were
3.7 5.2 -4.7
the output might be
Sum: 4.2
Average: 1.4
2 of your 3 numbers are positive.

Also turn in sample runs with well-chosen test cases.

Scheme version:

Write three functions named sum, average, and count-positive. Each will take in three numbers and return a number: the sum of the three numbers, their average, or how many are positive, respectively.

If you want to practice with Scheme I/O, write a function named hw1 that takes no arguments, asks the user for three numbers, then prints out their sum, average, and how many are positive, as above. Hint: use the functions you just wrote!

Prolog version:

Write three 4-place predicates named sum, average, and count_positive. Each one expects its first three arguments to be bound to numbers, and binds the fourth argument to a number as appropriate.

If you want to practice with Prolog I/O, write a 0-place predicate named hw1 that asks the user for three numbers, then prints out their sum, average, and how many are positive, as above. Hint: use the predicates you just wrote!


Last modified: 
Stephen Bloch / sbloch@adelphi.edu