CS 223 - Spring 2017. 3/8

Welcome to CS 223!

Larry Wall Quote of the day

Yes, you can think of almost everything as a function, but this may upset your wife.

Logical problem of the day

#include <stdio.h>
#define BUFSIZE 2048 

int main(){
  int n = BUFSIZ;
  printf("n = %d\n", n);
}

What's up up there?

Lecture 15: HW5 + Data Structures: btrees

Administrivia

Office hours:

The office hours are Sun/Tue/Thu 8-11 PM at Hillhouse 17 Rm 111.

My office hours this week are Wednesday 3-5pm.

Mid term exam

Grades have been posted to classes v2.
Will return exams in class on Wednesday.
Problem 1a
Problem 1b
Problem 2 is in K&R, string reverse
Problem 3 lists I think with number 3, the main issue people had was with what to malloc, how much space to malloc, traversing a linked list (without moving the head of the linked list), when to reference/dereference/what does * mean?, deleting.
However, that being said, this is all stuff that they should have known because this is all stuff they should have done for Callme.
Some students were confused when they should and when they shouldn't. Besides, I saw some very tricky mistake that students free the pointer in a list and then call that pointer's next. Temporary variable should be set for the next before freeing the pointer.
Problem 4 hash For number 4, what most people got wrong was how to free the malloc'ed structures, as well as what to malloc exactly.
Problem 5 string data type For number 5, mallocing seemed like the primary issue (primarily mallocing space for the struct itself, in addition to the string). There was also confusion because the problem's function headers included only the parameter types; when writing the functions, students should remember to give each parameter a name, instead of trying to use the name of the datatype.
Problem 6 Nodup

Many of you emailed me regarding hw3 grading issues. Subsequently, there has been related discussion on piazza. You should rely on those postings, which means that you should resubmit (by this Friday). If your issues are different, then contact cs223help@cs.yale.edu.

Assignment 4

There has been some discussion on piazza about the debug option showing the updated string values in the stack after the numeric value has changed, for example, @303 The TA's/ULA's have recommended that we modify the spec to do the right thing. They will post an update to piazza. The debug tests will be modified accordingly. BTW, my previous suggestion about implementing ftoa() has been superceded by the suggestion of using sprintf(). For those of you who have finished hw4, adding and testing this modification should not take more than 30 minutes or so.

Assignment 5

Problem set 5

Here is an example: Alice In Wonderland cloud

Here is an example: Alice In Wonderland cloud with threshold=10

Lecture Starts Here

Binary Trees

A btree for integers btreeint.c (from Aspnes) [malloc issue: sizeof(struct node) == sizeof(*newNode) != sizeof(newNode)] -- added treePrint()
A btree for integers btreeintargs.c with command line arguments. -- added treePrint()
The header file btree.h Note: there is no treeDelete function. (sigh of relief)
The test file btreetest.c (continue here) -- added treePrint()
The arg test file btreetestargs.c -- added treePrint()
Data Structure Visualizations
Binary search tree animation
Balanced trees
AVL Trees AVLtree.h AVLtree.c AVLtree.output AVL animation

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