CSC321.01 2017S, Class 02: Getting Started with Ruby

Overview

• Preliminaries.
  • Admin.
  • Upcoming Work.
  • Questions.
• Ruby
• Some Ruby Problems

Preliminaries

Admin

Notes

• We now have a schedule in place. The rest of the syllabus should be there tonight.
• I lied. Most students last year said they took 4-5 hours. That means I’ve used about half of your homework time for this week (assuming that you got through everything).
• How long did the Ruby thing take?

Homework

• More Ruby (soon to appear in assignments)
• Reading journal (in assignments)

Good Things To Do

Note

Questions

Ruby

What’s something familiar?

What’s something new and exciting you’ve discovered about Ruby?

How does Ruby handle a programmer’s need for multiple inheritance?

What is something particularly confusing or puzzling in the Codecademy tutorial?

Other comments …

Some Ruby Problems

We did not get to this section. You are likely to do it in homework.

Write sums_to_n?(vals,val) that returns true if any two distinct values from vals (a list of values) sums to val.

• sums_to_n?([1,2,7],5) -> false
• sums_to_n?([1,2,7],3) -> true
• sums_to_n?([1,2,7],8) -> true
• sums_to_n?([1,2,7],9) -> true
• sums_to_n?([1,2,7],4) -> false

Write multiple_of_4?(bitstring) that takes a string of 0’s and 1’s (representing an unsigned integer) as input and returns true if the string represents an integer divisible by four.

Write starts_with_consonant?(str) that determines if a string starts with a consonant.