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=Rhea Section for ECE 264 Professor Yung-Hsiang Lu, Spring 2012=
 
  
 
Lecture 3
 
 
Lecture 3 – 1/17/2012
 
 
In class quiz – Know 3 or more classmates, their names, hometown, interests, career goals (submitted at the end of class)
 
 
Reminder
 
• Exercise 1 due this coming Friday (January 20th)
 
• Write Programs in EE206
 
• Check blackboard everyday
 
• Submit your signature on the class policy sheet given the first day of class
 
• Office Hours:
 
o Tuesday and Friday after class in MSEE222, open door policy. You can discuss any topic.
 
 
Today’s Programs
 
• Review of simple C programs
 
• Programming in Linux
 
• Maze files and rules
 
• Arc and argv
 
• Program to read characters in a file
 
• Function calls
 
• Practice how to write a program that can find 26 English characters and tell which ones appear the most often (ignore cases)
 
• Challenge: Write a program that can generate valid mazes
 
 
In Linux…
 
• mkdir → makes a new directory (folder)
 
o EX: mkdir ECE264
 
• ls → lists the files in the directory
 
o EX: ls
 
• cd → changes the directory
 
o EX: cd Exercises
 
• File → determines what type of file you are dealing with
 
o EX: file prog1 (returns a ‘.c’ file type)
 
• emacs/vi filename.c → creates a file and puts it into a text editor of choice
 
 
NOTE: Make sure never to have space in file name
 
 
• What is used to compile programs?
 
o   Linux:         gcc prog1.c -o prog1
 
o   Translation: Compiler    Human Readable  Name of Output file  Machine Readable
 
 
o   Linux: ./(no space)ex1 data
 
o   Translation: Run Machine Readable and use a text file called data
 
 
Example 1:
 
 
a =1
 
b=2
 
if(a>b)
 
printf(“…”);
 
a = 5
 
 
What is the value of ‘a’ here? a = 5.
 
 
• In the statement above, it doesn’t matter what is inside the if statement because ‘a’ is later redefined to be a OUTSIDE the if statement
 
• Always remember to use brackets with all logic statements
 
• No “end” in C (as in MATLAB if statements)
 
 
Indexing
 
• In C, index always begins with 0
 
 
int arr[6];
 
 
for( c = 0; c < 6; c++)
 
{
 
c will be 0,1,2,3,4,5
 
}
 
 
It is wrong to do the following:
 
 
int arr[6];
 
 
for( c = 0; c <= 6; c++)
 
{
 
c will be 0,1,2,3,4,5,6 ERROR: INDEX OUT OF RANGE
 
}
 
 
Inputting a string
 
• scanf(“%s”, str);
 
• printf(“%s”, str);
 
 
Maze program:
 
• Each wall is one layer thick
 
• Always one exit, one start
 
• Always one solution
 
• Pathways are on * in length
 
 
argc and argv
 
• Same as for function arguments,
 
 
int add( int a , int b)
 
 
• But instead,
 
 
Int main ( int argc , char *argv[] )
 
 
(# of arguments, array of each argument)
 
 
argv element#
 
 
0            . /     a     r     g   s     \0      (What is stored in row 0)
 
 
1            d             a     t     a   \0                (What is stored in row 1)
 
 
....
 
 
 
• The first argument is always the name of the command
 
• Several spaces count only as 1 space separating the arguments
 
 
 
[[Category:ECE264Spring2012Yung-Hsiang Lu]]
 

Revision as of 11:29, 22 January 2012

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Correspondence Chess Grandmaster and Purdue Alumni

Prof. Dan Fleetwood