1. EECE.2160 ECE Application Programming
Instructor:
Dr. Michael Geiger
Fall 2018
Lecture 2:
Basic C program structure
IDE demo

2. ECE Application Programming: Lecture 2
Lecture outline
Announcements/reminders
Chapter 1 exercises due Monday, 9/10
Textbook exercises always due 3 days after related lecture—check ”Assignments” tab regularly!!!
Program 1 due Wednesday, 9/12
10 points: register for access to the course textbook
10 points: introduce yourself to your instructor
30 points: complete simple C program
Today’s lecture
Basic C program structure
Comments
IDE demo
5/31/2019
ECE Application Programming: Lecture 2

3. ECE Application Programming: Lecture 2
Our first C program
#include <stdio.h> int main() { printf("Hello World!\n"); return 0; }
5/31/2019
ECE Application Programming: Lecture 2

4. ECE Application Programming: Lecture 2
Our first C program
# indicates pre-processor directive
include is the directive
stdio.h is the name of the file to "insert" into our program. The <> means it is part of the C development system
#include <stdio.h> int main() { printf("Hello World!\n"); return 0; }
5/31/2019
ECE Application Programming: Lecture 2

5. ECE Application Programming: Lecture 2
Our first C program
main is the name of the primary (or main) procedure. All ANSI C programs must have a main routine named main
The () indicates that main is the name of a procedure. All procedure references must be followed with ()
#include <stdio.h> int main() { printf("Hello World!\n"); return 0; }
5/31/2019
ECE Application Programming: Lecture 2

6. ECE Application Programming: Lecture 2
Our first C program
{ } enclose a "block". A block is zero or more C statements. Note that code inside a block is typically indented for readability—knowing what code is inside the current block is quite useful.
#include <stdio.h> int main() { printf("Hello World!\n"); return 0; }
5/31/2019
ECE Application Programming: Lecture 2

7. ECE Application Programming: Lecture 2
Our first C program
printf() is a "built-in" function (which is actually defined in stdio.h).
"Hello World!" is the string to print. More formally, this is called the control string or control specifier.
#include <stdio.h> int main() { printf("Hello World!\n"); return 0; }
Every statement must end with a ";". Preprocessing directives do not end with a ";" (but must end with a return).
5/31/2019
ECE Application Programming: Lecture 2

8. ECE Application Programming: Lecture 2
Our first C program
The \n is an escape character used by the printf function; inserting this character in the control string causes a “newline” to be printed—it’s as if you hit the “Enter” key
#include <stdio.h> int main() { printf("Hello World!\n"); return 0; }
5/31/2019
ECE Application Programming: Lecture 2

9. ECE Application Programming: Lecture 2
Our first C program
The int tells the compiler our main() program will return an integer to the operating system; the return tells what integer value to return. This keyword could be void, indicating that the program returns nothing to the OS.
#include <stdio.h> int main() { printf("Hello World!\n"); return 0; }
5/31/2019
ECE Application Programming: Lecture 2

10. Variations #1 of first program
#include <stdio.h> int main() { printf("Hello"); printf("there"); printf("World!"); return 0; }
5/31/2019
ECE Application Programming: Lecture 2

11. Variations #2 of first program
#include <stdio.h> int main() { printf("Hello\n"); printf("there\n"); printf("World!\n"); return 0; }
5/31/2019
ECE Application Programming: Lecture 2

12. Variations #3 of first program
#include <stdio.h> int main() { printf("Hello\nthere\nWorld!\n"); return 0; }
5/31/2019
ECE Application Programming: Lecture 2

13. Variations #4 of first program
#include <stdio.h> int main(){printf ("Hello\nthere\nWorld!\n");return 0;}
Note while this is syntactically correct, it leaves much to be desired in terms of readability.
5/31/2019
ECE Application Programming: Lecture 2

14. ECE Application Programming: Lecture 2
Code readability
Readability wouldn’t matter if:
Entire code project written by one person
All code was in same file
Same person is the only one to use the code
Code was used only for a short period of time
More typically:
Projects are split—multiple programmers and files
Code usually reused
Multiple users
Used/adapted (hopefully) over long period of time
You may reuse code ... but forget what you originally wrote!
Bottom line: code needs to be readable
5/31/2019
ECE Application Programming: Lecture 2

15. ECE Application Programming: Lecture 2
Comments
C allows you to add comments to your code
Single line comments: start with //
Multi-line comments: start with /*
end with */
Typical uses
Multi-line comment at start of program with
Author’s name (& other info if appropriate)
Date started/modified
File name
Description of overall file functionality
For individual code sections
Single/multi-line comment for major section of code performing single function
Single line comment for single line of code if that line alone is important
5/31/2019
ECE Application Programming: Lecture 2

16. ECE Application Programming: Lecture 2
Comment example
/* ECE Application Programming Instructor: M. Geiger 5/31/2019 hello.c: Intro program to demonstrate basic C program structure and output */ #include <stdio.h> // Main program: prints basic string and exits int main() { printf("Hello World!\n"); // Comment return 0; }
5/31/2019
ECE Application Programming: Lecture 2

17. ECE Application Programming: Lecture 2
Assignment #1
Basic assignment to ensure you can write, run, and submit programs
Write a short program that prints (each item on its own line):
The name of the class
The current semester
The days on which lectures meet
The instructor’s name
For this assignment, spacing matters!!!
5/31/2019
ECE Application Programming: Lecture 2

18. ECE Application Programming: Lecture 2
IDE demo
Basics of writing and compiling code
Develop mode vs. submit mode
Dealing with errors
Test cases
5/31/2019
ECE Application Programming: Lecture 2

19. ECE Application Programming: Lecture 2
Final notes
Next time
Data types
Variables
Reminders
Chapter 1 exercises due Monday, 9/10
Textbook exercises always due 3 days after related lecture—check ”Assignments” tab regularly!!!
Program 1 due Wednesday, 9/12
10 points: register for access to the course textbook
10 points: introduce yourself to your instructor
30 points: complete simple C program
5/31/2019
ECE Application Programming: Lecture 2