CIS71 Computer Programming in C

CIS 71: Computer Programming in C Class Log Fall 2006

12/01/06 - Class on 12/05/06 - Last class

Review from the beginning.
Questions?
Enumerating the elements of a square matrix.
By now we should be able to solve in C programming problems that have solutions as one or two hundred line programs, possibly spanning a number of files.
The exam is on Thursday, December 14, from 8:30am to 10:30am in our class.

11/28/06 - Class on 11/30/06

Returned and discussed the last 5-minute test
Review: Formal parameters, local variables, global variables.
Review: Compiling, linking, and executing
Review: Reasoning about programs - preconditions, postconditions, invariants, complexity.
Reading a sequence of integers and printing, as they are read, their ordinal, their value, the minimum value, the average, and the maximum value
Class evaluation

11/21/06 - Class on 11/28/06

Review: I/O
Review: strange declarations: char **a, int (*b)[7], int *c[7], void *foo(), int (*f)(int x)
Pointers to functions and their use.
Partitioning an array of integers.
Collision resolution in a hash table, linear, quadratic, rehashing.
Eleventh 5-minute test

11/17/06 - Class on 11/21/06

Review: expressions
Review: control statements
Review: debugging and testing
Rotating the elements of an array.

11/14/06 - Class on 11/16/06

Returned and discussed the tenth 5 minute test
Review: derived data types
A hash function

11/12/06 - Class on 11/14/06

Review: identifiers - what uses have we found for identifiers?
Review: Scope of definitions
Review: primitive data types
Generating random permutations
Counting the number of occurrences of each word in a text file. How do we know we have already met a word? Search problem; linear search, binary search, hashing.
Last homework
Tenth 5-minute test.

11/08/06 - Class on 11/09/06

Returned and discussed the ninth 5-minute test
The union data type.
Merging two sorted files
Reading from the keyboard: play it safe and use fgets, then parse the line you have retrieved.
Finding the words (words, not tokens, i.e. they must be formed only of letters) in a line.

11/04/06 - Class on 11/07/06

Returned and discussed the eight 5-minute test.
Merging two sequences of integers
The enum data type. Examples of declarations
Enumerating the words in a file.
Eleventh homework
Ninth 5 minute test

10/31/06 - Class on 11/02/06

Opening, closing a file. Reading and writing from/to a file. fprintf, fscanf, fgets, fputs, getc, putc. Recognizing the end of a file, feof.
An example of reading a file
Copying a file
Random numbers. A simple random number generator.
Bubble sort.
Eight 5-minute test

10/28/06 - Class on 10/31/06

Returned and discussed the second midterm
Using typedef.
Repeated concepts about structures.
Files: text files vs binary files; sequential access vs random access.
Tenth homework.
The TA has asked me to extend the deadline for last homework to Friday November 3.
No 5 minute test today. We will have it on Thursday.

10/19/06 - Class on 10/26/06

Second Midterm.

10/19/06 - Class on 10/24/06

This Thursday we are having our second midterm.
.h files and separate compilations.
Global variables [don't use them unless you have a good reason to].
Combining in a single data structure various kinds of data: the use of struct. Anonymous and tagged structures. Dotted notation. Assignment. Structures are passed to functions by value.
Nineth Homework
Seventh 5-minute test

10/17/06 - Class on 10/19/06

Returned and discussed the sixth 5-minute test.
Again: Two dimensional arrays are really stored as one dimensional arrays.
Again: arrays and pointer arithmetic.
Bitwise operators: &, |, ^, ~, <<, >>
The const attribute.
Declaration vs. Definitions. Function prototypes.
Insertion sort.

10/14/06 - Class on 10/17/06

Remember that we can use standard functions to work with strings, things like strlen, strcpy, strcmp, ..
Parameter passing: Mode - IN, OUT, INOUT
Two dimensional arrays.
Transposing a square array (i.e. two dimensional, with same order in each dimension).
Two dimensional arrays are really stored as one dimensional arrays.
Eight Homework
Sixth 5-Minute Test

10/10/06 - Class on 10/12/06

Returned and discussed the fifth 5 minute test
Reading a line: fgets, stdin. Beware of buffer overflow.
Selection sort.
More reasoning about programs
Operations on C strings: strlen, strcpy, strncpy, strcat, strncat, strcmp, strncmp. They are part of the Standard C library. But we could write them ourselves.

10/05/06 - Class on 10/10/06

int main(int argc, char * argv[]) : Command line parameters.
Reasoning about programs. Preconditions, postconditions, loop invariants, complexity of computation.
Seventh homework.
Fifth 5-minute test

10/03/06 - Class on 10/05/06

Returned and discussed the fourth 5-minute test.
Review of stubs and drivers.
Representation of strings in c. sizeof and strlen.
Reading an integer by processing a sequence of digits.
Back to arrays. The sum of the elements of an array.
Finding a value in an array: Linear search.
Starting: Reasoning about programs.

09/28/06 - Class on 10/03/06

Formatting a program.
Arrays: declaring and using a one dimensional array.
Finding the largest element in an array.
Reversing an array.
Formatting the output. Conversion letters: d, u, x, o, e, f, c, s, p. Size and precision modifiers. Flags: 0, space, +, -, #. A simple example.
Handed out sixth homework
Fourth 5 minute test.

09/26/06 - Class on 09/28/06

Returned and discussed the first midterm.
Printing out the successive squares of integers
Writing our own square root function
Stubs and drivers.
Looking again at expressions and their syntax. There are some funny looking expressions: suppose x is an integer variable, then I can use (x=3) as an expression with value 3 and side effect to set x to 3 [avoid unless you have super reasons to do it]. And there is also the conditional expression: for instance (x<=y)?x:y which returns the smaller of x and y [again, avoid unless really convenient].
The switch statement.
The do while statement.

09/19/06 - Class on 09/26/06

First Midterm.

09/19/06 - Class on 09/21/06

Next Tuesday we have our first Midterm. Review most of the first 7 chapters. We have skipped a number of topics, for example the switch statement and the do..while statement. Look carefully at this class log and to your class notes.
Returned and discussed the third 5-minute test
Scope of an identifier.
Global variables [use with extreme moderation and caution].
Using the C math library
More about loops: using sentinels, off-by-one errors, the do while loop.
Break and continue.
To not disturb you next Tuesday with the next homework, here is the homework that is due for Tuesday October 3.

09/14/06 - Class on 09/19/06

Given list of C keywords and chart of operator precedences
When using scanf we have used the operator '&' that applied to an integer x returns the address of that variable (of the memory associated to the variable). We can store that address in a variable of type "int *". In fact we can say, assuming we had declared int x,
```
	int * y = &x; /* read: the type of y is the address of an integer.
			 Its value is the address of x. */
```
Back to functions: formal parameters versus actual parameters, i.e. values used when calling a function.

Parameters are passed to a function by value. For example the function

	void swap(int x, int y) {
	    int temp = x;
	    x = y;
	    y = temp;
	}

in the following program

	int a = 2; 	int b = 3;	swap(a, b);

will leave a and b unchanged. But if we write instead

	void swap(int *x, int *y) {
	    int temp = *x;
	    *x = *y;
	    *y = temp;
	}

and call with

	int a = 2; 	int b = 3;	swap(&a, &b);

now the values of a and b are truly swapped.

Introducing a constant value: #define. Compiler directives.
Printing addresses: %p
Fourth homework.
Third Five-minute test.

09/12/06 - Class on 09/14/06

Returned and discussed second 5 minute test.
Errors in our programming: syntactic errors, semantic errors, logical errors.
Debugging vs. testing.
Printf and scanf, %d, %f, %lf, %s, %c
Computing the greatest common divisor of two integers.

09/07/06 - Class on 09/12/06

Abbreviations: ++, --, +=, -=, *=, /=, ..
Writing functions. void. return statement.
Recognising if a number is a prime.
Mapping integers to characters and viceversa (ASCII).
Third homework
Second 5 minute test.

09/07/06 - Class on 09/07/06

Returned and discussed the results of the last 5 minute test.
Declarations
Conditional expressions
Mixed type expressions and assignments. Casting.
More expression evaluations
The block statement
The conditional statements
The while loop
The for loop

09/01/06 - Class on 09/05/2006

Briefly, the basic data types: int, float, char. Binary integer representation. How to use boolean values.
Overflow errors and roundoff errors.
Variable declaration.
Starting with expression evaluation. Priority of operator. Left to right processing.
Assignment statement.
Reading and writing an integer or a string
Used the if-else statement and the while and for loops.
First 5-minute test.
Second homework.

08/30/06 - Class on 08/31/2006

The process of creating a program: problem statement/requirements, analysis, design and algorithms, implementation, testing.
The mechanics of creating a program: editor, compilation/linking, executing
Example of a C program: Printing out a table of Fahrenheit/Celsius conversions. We will have to understand in time a lot of the issues touched in this program.
Scan quickly (do not need to remember much) Chapter 2.
First homework.
Our 5-minute tests will be on Tuesdays (unless told differently in advance). So our first test will be next Tuesday.

08/30/06 - Class on 08/29/2006

We have gone over the syllabus in its various aspects, objectives of the course, people involved, text book, grading, etc.
We have discussed what is a computer system, with its CPU, main memory, secondary storage, bus, input, and output. We have done this mentioning things like bytes, megahertz, nanoseconds, ..
We have discussed programming languages and C
We have named trivia: powers of 2, milliseconds, microseconds, nanoseconds, picoseconds, kilobytes, megabytes, gigabytes,terabytes, petabytes, Hz and GHz
Read Chapter 1.
Our first lab is thursday at 2:40 in Wachman Hall, room 104. In the lab we will hand out the accounts for the course. We will see how to disassemble and reassemble a computer. We will see how to log on Unix and on Windows. We will see how to edit a text file, how to compile it, how to run it. We will see how to send a program to the instructor using email.

08/14/06 - Before Class on 08/29/2006

This is hard to do, since probably you will not look here until after the first day of class. But if you can, try to review what you learned in previous programming classes, if any. Start reading the first couple of chapters of the textbook.