CS 223 - Spring 2017. 2/1

Welcome to CS 223!

Logical problem of the day

tolower.c revisited:
int main(){
  char * w = "HELLO";
  char z[6];
  int len = strlen(w);
  printf("len: %d\n", len);
  for (int i=0; i < len; i++){
    printf("w[%d] = %c (%c)\n", i, w[i], tolower(w[i]));
    // w[i] = tolower(w[i]); caused a seg fault.  why?
    z[i] = tolower(w[i]);
  printf("w: %s\n", z);
This code now works. Why did the w[i] line cause a segmentation fault?

Bonus logical problem:

In one line of UNIX, generate the file words containing only 7 letter words from /usr/share/dict/words

Lecture 6: Introduction to C: hw3 + guest speaker


  • Office hours:
    We have added the public tests for assignment 2. The office hours are Sun/Tue/Thu 8-11 PM at Hillhouse 17 Rm 111.
  • Reminder to speaker: use the microphone in Davies.

  • Notetaker needed for this course immediately: $12.75 / hour. If you are interested, please email Carolyn Barrett (carolyn.barrett@yale.edu) at the Resource Office on Disabilities specifying the name of this course (CSPC 223) and the professor (Stephen Slade).

    Guest Speaker

    Michael Ljung, Managing Director, Accenture, Yale '92.
    Lessons learned in program management, technology, and innovation at Healthcare.gov


    The Patient Protection and Affordable Care Act (also known as Obamacare) created new Health Insurance Exchanges, at both the State and Federal level. These exchanges are public-private marketplaces where Americans can apply for a tax subsidy and shop for health insurance plans, across insurance companies. Healthcare.gov, the website for the Federal exchange, is the front door for the Federally Facility Marketplace, or FFM. Many people are aware that the initial launch of healthcare.gov had a number of challenges, which received extensive coverage and political, media, and public scrutiny. People may not be aware, though, that the FFM is much more than just a web site. It includes a plan management system for loading healthcare plans onto the website; interfaces with State and Federal systems; interfaces with insurance companies for enrollment, premium payment, and reinsurance programs; interfaces with the IRS for the tax subsidy; and a new SHOP program for small businesses.

    A rescue of the web site began in November 2013, and in January 2014, the Federal government hired Accenture Federal Services as the prime development contractor, with responsibility for stabilizing and improving the web site and finishing development of the additional systems and interfaces. This talk will address the steps that Accenture and the Federal government together took to deliver successfully…so millions of Americans could ultimately enroll and get access to healthcare, many for the first time.


    Michael Ljung is a Managing Director at Accenture Federal Services. He is the delivery lead for all of Accenture’s work on the FFM. Prior to that, Michael was the North America lead for Accenture’s Advanced Systems & Technology practice. This group included 2,500 experts in technology architecture, custom development, agile methods, mobility, and cloud computing. Michael has worked for clients in the public sector and Fortune 500, across industries. He also has extensive international experience, including helping set up the company’s component technology centers in southern France and London.

    Michael joined Accenture after graduating from Yale with a B.S. in Computer Science and a strong interest in music theory. He was a member of the Yale chapter of Tau Beta Pi. Since his bright college years, he has been to all but one of the Yale-harvard football games.

    Assignment 3

    Problem set 3

    Lecture Starts Here


    Aspnes: Pointers