EP3BB3 Lab #1-2024/25-V1.3
Lab 1: Introduction to C Programming
1 Introduction
This lab serves as an introduction to C programming language for those who may be new to it, and a
refresher for those familiar with it. The aim is not an in-depth exploration of C but a review of the basics
through exercises to ensure your readiness for its applications in the upcoming labs.
1.1 Software Installation
In case you haven’t done so already, install Visual Studio Code and C using the instructions provided on
Avenue to Learn. Please note that this step is time consuming and therefore, you should do this ahead
of your lab.
1.2 Hello World!
To ensure that you have set up Visual Studio Code correctly, open Visual Studio Code and create a New
File. Name it as you want as file_name.c. Copy the following code:
#include <stdio.h>
int main(void){
printf("Hello World!");
return 0;
}
Then use the icon “Debug C/C++ File” from the top right corner of the page (see the image below). You
should see the phrase “Hello World” in the terminal window. Now that we confirmed everything works,
let’s get to the lab!
EP3BB3 Lab #1-2024/25-V1.3
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2 Lab 1 – The Real Thing
In this lab, we will have different exercises with a strong focus and emphasis on binary and bitwise
operations as these will be an essential concept throughout this semester.
2.1 Sample Program
Recommended duration for task completion: 10 minutes
Recall this program from your lecture notes which reads three integer values from the user and prints the
average. Let’s quickly review this program:
#include <stdio.h>
int main(void)
{
int value1, value2, value3;
float sum, average;
printf("What is the first value? ");
scanf("%d", &value1);
printf("What is the second value? ");
scanf("%d", &value2);
printf("What is the third value? ");
scanf("%d", &value3);
sum = value1 + value2 + value3;
average = sum / 3;
printf("The average of %d, %d, and %d is %f\n", value1, value2, value3,
average);
return 0;
}
We will be using this example to introduce debuggers! Debuggers help you inspect different portions of
the code and understand how different variables change as the program runs. You can add “Breakpoints”
to force your code to pause when it reaches certain points. To enable breakpoints for different lines, you
can simply click in the area next to the line number (see below). EP3BB3 Lab #1-2024/25-V1.3
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In the example above, we have added two breakpoints in lines 17 and 18. When you run the code by
pressing Debug C/C++ File, an icon bar appears on the top of screen and when it reaches the breakpoint,
it will look similar to the image below. Visit this page and review the “Debug actions” table to learn more
about these icons.
Now, the values for different variables before calculations of lines 17 and 18 are listed on the left side of
your screen (see below, picture “a”). When you press “Step Over” from the icon bar above, the values will
be updated (see below, picture “b”).
In addition, after running the debugger, you can right click on any variable in your code and select “Add
to Watch” to inspect that variable.
Task #2.1: Use the debugger yourself and explain the program above to your TA line by line.
(a) (b) EP3BB3 Lab #1-2024/25-V1.3
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2.2 if-else Conditional Statements
Recommended duration for task completion: 20 minutes
Task #2.2: Write a program that reads a non-zero number from the user and determines if it is even or
odd. Explain the program to your TA line by line.
#include <stdio.h>
int main(void)
{
// Declare an integer.
printf("Please enter a non-zero number: ");
// read the number from the user using scanf.
// In the following if statement, determine if the number is divisible by 2
using the modulo operator.
/*
if (CONDITION) {
// Print the entered number is even/odd. You must show the number entered
by the user.
}
else {
// Print the entered number is odd/even. You must show the number entered
by the user.
}
*/
return 0;
}
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2.3 While Loops
Recommended duration for task completion: 20 minutes
Task #2.3: Write a program, using while loops, that writes numbers from 1 to 10. Explain the program to
your TA line by line.
#include <stdio.h>
int main(void){
// Declare an integer here and initialize it with a reasonable value.
// The while loop (below) prints the integer and then increments it, as long
as it satisfies the CONDITION.
// while (CONDITION) {
// Print the integer.
// Increment the integer.
}
return 0;
} EP3BB3 Lab #1-2024/25-V1.3
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2.4 For Loops
Recommended duration for task completion: 20 minutes
Task #2.4: Write a program, using for loops, that prints all the even numbers between 1 to 10. Explain the
program to your TA line by line.
#include <stdio.h>
int main(void){
// Declare an integer.
//The for loop (below) should go through the numbers from 0 to 10 and check
if the number is divisible by 2.
//for (start from 0 and increment until 10){
/*if (divisible by 2, for example using the modulo operator){
// Print the value.
}
else
{
// Don't do anything.
}*/
}
return 0;
}
EP3BB3 Lab #1-2024/25-V1.3
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2.5 User-Defined Functions
Recommended duration for task completion: 20 minutes
Task #2.5: Rewrite the sample program of task 2.1. Once the user inputs three integers, pass them to
another function called averageCalculator, which calculates the average and returns the value to the main
function. The main function, then, prints the calculated average value. Explain the program to your TA line
by line.
#include <stdio.h>
float averageCalculator (int a, int b, int c);
float average;
int main(void)
{
int value1, value2, value3;
printf("What is the first value? ");
scanf("%d", &value1);
printf("What is the second value? ");
scanf("%d", &value2);
printf("What is the third value? ");
scanf("%d", &value3);
// Call the averageCalculator function and pass the values.
printf("The average of %d, %d, and %d is %f\n", value1, value2, value3,
average);
return 0;
}
// Define a function name averageCalculator which reads three integers (as
arguments) and returns the parameter average as a float.
/*
return_type averageCalculator(arguments)
{
Do the calculations here and return the average!
}
*/
EP3BB3 Lab #1-2024/25-V1.3
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3 Bitwise operations
Due to the importance of bitwise operations in the future labs, we will now work on some exercises
related to this topic.
3.1 Exercise 3.1
Recommended duration for task completion: 30 minutes
Task #3.1: Study and complete the following code. In this code, the user enters two decimal numbers. The
code will calculate different bitwise operations and prints the results represented in decimal. For example,
take a value of 7 for a (0000 0111 in binary) and a value of 12 for b (0000 1100 in binary). A bitwise AND
of these values is 4 represented in decimal which is 0000 0100 in binary. Complete the code, use a
different set of input number, and show that your results from your on-paper calculations and those
derived from your code match.
#include <stdio.h>
int main(void)
{
int a, b;
printf("What is the first value (in decimal)? ");
scanf("%d", &a);
printf("What is the second value (in decimal)? ");
scanf("%d", &b);
printf("The bitwise AND of %d, and %d, REPRESENTED IN DECIMAL, is %d\n", a,
b, a & b);
// Print the bitwise OR of the two numbers.
// Print the bitwise XOR of the two numbers.
// Print the bitwise NOT of one of the numbers.
// Print the bitwise left shift (shifted by one bit) of one of the numbers.
// Print the bitwise right shift (shifted by one bit) of one of the numbers.
return 0;
}
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3.2 Exercise 3.2
Recommended duration for task completion: 30 minutes
Imagine you are in a room which has 8 LED light switches controlling 8 different LED lights. Of course, at
any given time, each light can be either on or off. The goal is to independently control these LEDs without
unintentionally affecting the others. Maybe you want to turn on (or SET) specific LEDs. Maybe you want
to turn off (or CLEAR) some or all of them. Maybe, and maybe, you want to flip (or TOGGLE) specific ones.
Or perhaps, you want to play a prank on your roommate by flipping all the switches, turning on what’s off
and turning off what’s on (INVERT).
LED 7 LED 6 LED 5 LED 4 LED 3 LED 2 LED 1 LED 0
OFF OFF ON OFF ON OFF ON ON
Well, as it turns out, this is what your microcontroller looks like. For instance, PORT1 of your
microcontroller has 8 pins (labeled from 0 to 7). Let’s do ourselves a favor and consider them a binary
sequence. Each pin can have a value of 0 or 1 (i.e., binary). In these cases, it is important to know the
current state of the system as well as the change you want to impose on the system. You can then
calculate the final state of the system using the bitwise assignment operators. These are basically the
same bitwise operators from Exercise 3.1, however they are now followed by the assignment “=” sign. So,
what’s the difference?
The bitwise AND assignment (&=) first calculates the bitwise AND operation between operands and then
assigns the value to the left operand. It can be used to clear bits.
The bitwise OR assignment (|=) first calculates the bitwise OR operation between operands and then
assigns the value to the left operand. It can be used to set bits.
The bitwise XOR assignment (^=) first calculates the bitwise XOR operation between operands and then
assigns the value to the left operand. It can be used to toggle bits.
Lastly, the operation ~ can be used to invert bits: turning all ones to zeros and vice versa.
Let’s work through an example. Imagine the initial state of the system of LEDs in the table above is 0010
1011 (equivalent to 43 in decimal), where each bit represents the state of a specific pin, with 0 and 1
indicating states such as ON/OFF. Now, let’s say you want to turn off all LEDs except the 6th bit (or LED #5)
i.e., 0010 0000 (or 32 in decimal). You can CLEAR using the bitwise AND assignment operation (&=). Use
the following code for a practical demonstration.
Task #3.2: After making this observation, complete the code below to calculate the bitwise OR assignment
and the bitwise XOR assignments for a different set of input states (initial state and change). Show that
your results from your on-paper calculations and those derived from your code match. More importantly,
explain how these different operations can be used to set/clear/toggle/invert bits.
EP3BB3 Lab #1-2024/25-V1.3
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#include <stdio.h>
int main(void)
{
int initialstate, change, tempstate;
printf("What is the initial state (in decimal)? ");
scanf("%d", &initialstate);
tempstate = initialstate;
printf("What is the change (in decimal)? ");
scanf("%d", &change);
initialstate &= change;
printf("The &= of %d, and %d is %d\n", tempstate, change, initialstate);
return 0;
}
EP3BB3 Lab #1-2024/25-V1.3
4 Code Submission
Codes for all tasks must be submitted before the deadline (Jan 12th, 2025 by 7:30 PM EST) on Avenue to
Learn.
EP3BB3 Lab #1-2024/25-V1.3
5 What’s Next?
5.1 Assessment and Reflection on the Lab
Spend a few minutes and reflect on what you learned today. Your TAs will assess your lab based on your
understanding and explanation of what you have done, observed, and learned during this lab (and the
pre-lab when applicable). Explain the technical details to your TAs and share your takeaways of the lab.
Half of your mark for the lab is dedicated to your code and its functionality and the other half to your
understanding and explanations.
Even though you are working in groups of 2, you are expected to write your own codes and do each tasks
individually. However, you are encouraged to discuss your approach with your lab partner.
5.2 Tidying Up
Firstly, great work finishing your lab! You can leave the lab after cleaning your workstation:
• Remove the jumper wires from your breadboard and dump them in the wire containers on your
workstation.
• Remove the components from your breadboard and place them in the component containers at
your workstation. Make sure to put the components back in the right drawers.
• Disconnect the probes from your power supply, function generator, multimeter, and oscilloscope,
and hang them from the wire rack on the wall.
• Remove any pieces of paper, garbage, etc., from and clean your workstation before leaving the
lab.
Note: You are always expected to clean your workstation before leaving the lab.
5.3 Next Lab’s Preparation
The lab manual for the next lab on “Introduction to Microcontrollers” is available on Avenue to Learn.
Please review the lab manual before attending the lab. In particular:
• Follow the instructions published on Avenue to Learn to purchase the microcontroller and bring
your microcontroller to the lab.
• Before coming to the lab, you must review the prelab and follow the instructions to install
CCSTUDIO — Code Composer Studio™ integrated development environment (IDE). This should be
done before coming to the lab.
• After installing the IDE, follow the prelab’s blink test to make sure everything is set properly.
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