CMSC104 Summer 2012

Classwork 3: Our first C program

Thursday, July 12, 2012

Complete the following:

Ensure the machine is booted into Linux
Login to Linux
Open a termimal from the top left Applications menu -> System Tools -> Terminal
Create a directory (using mkdir) called cw03 to store this classwork
Go into your new cw03 directory (using cd)

Use ls and pwd to make sure you are in a directory called cw03

linux2[95]% mkdir cw03
linux2[96]% cd cw03
linux2[97]% pwd
/afs/umbc.edu/users/d/s/dsheets/home/cw03
linux2[98]% ls

Create a new file using nano called cw03.c

Type a comment for the header based on the template below:

/*   File: cw03.c
     Name: A. Student
     Username: astudent1
     Date: 10/24/07
     Description: A sample program
*/

Copy or type the following code into your cw03.c file following your header

#include <stdio.h>

int main(void)
{
  printf("Starting my program\n");
  return(0);
}

Compile your program as shown below
```
linux2[107]% gcc -Wall cw03.c -o cw03
```

Run your program as shown below

linux2[108]% ./cw03
Starting my program

Starting with the program code provided, add statements to get 3 values from the user, add those values together, and then print the result.
Make sure you change the file description comment to say what your file will do now
Test the program as you are writing it.
NOTE: Testing often is best. Don't write all the code then test. It is very useful to have two terminal windows open, one to edit and one to compile and run your progam.
Once you are sure the program is done and working well, start a script using script
Once the script is running, show you compiling your program, and then running the program three times, typing in different values each time.
Exit from the script, which will save the log typescript

An example of me running the script, compiling, and running my program is below

linux2[120]% script
Script started, file is typescript
linux2[1]% gcc -Wall cw03.c -o cw03
linux2[2]% ./cw03
Starting my program
Input value 1: 1
Input value 2: 2
Input value 3: 3
Total is: 6
linux2[3]% ./cw03
Starting my program
Input value 1: 6
Input value 2: 7
Input value 3: 2
Total is: 15
linux2[4]% ./cw03
Starting my program
Input value 1: 100
Input value 2: 200
Input value 3: 300
Total is: 600
linux2[5]% exit
exit
Script done, file is typescript

Once you are done, use submit to submit two files, cw03.c and typescript
```
linux3[26]% submit cs104 cw03 cw03.c typescript
```
After submitting your files, you can verify your files were submitted by using the submitls command as shown below
```
linux3[26]% submitls cs104 cw03
```
MAKE SURE YOU LOGOUT AFTER SUBMITTING THE ASSIGNMENT AND BEFORE LEAVING CLASS!

CMSC104

Problem Solving & Computer Programming

Classwork 3: Our first C program