Introduction to Computer Science - Fall 2009
CSCI 151
Lab 1   
Objectives:

Introduction to LINUX ,
emacs editor;
Compiling and executing C code.   

You don't need to submit this Lab Assignment. The first Lab Assignment that you will submit will be next week.

Lab Practice:

Part 1

1. Login to the system using your login name and the initial password
2. To change the password, type the following at the LINUX prompt
   yppasswd
   and follow the instructions.
   
   
3. Emacs Editor:
   Open emacs by typing the following at the LINUX prompt
   emacs hello.c &
   hello.c is the name of the file. Remember that a C program file name should end with an extension .c
   You can always open Emacs Tutorial through the Help Menu.
4. Type in the first C program that will print Hello World!
   Here is the program:

   /* My first program in C
   This program will print Hello World! */

   #include < stdio.h >

   /* function main begins program execution */

   int main()
   {

   printf ( "Hello World!\n" );

   return 0; /* indicate that program ended successfully */

   } /* end function main */

   To save your file use the File menu: File->Save
   
   
   

   To compile and run your C program read on how to compile and run C program
   
   

   Compile and run your program hello.c
   
   

   Basic file and directory manipulation commands.
   You will learn the following commands:
   ls - lists a contents of a directory
   rm- removes file
   rmdir - removes directory
   cp- the copy command
   mv- the move command
   mkdir - the make directory command
   cd- the change directory command
   pwd - the print working directory command
   
   
   
5. Try to use these commands. Do the following:
   • Create a new directory CSCI151 under your home directory by typing:
     mkdir CSCI151
     
     
   • type pwd to see the path to your home directory
     
     
   • type cd CSCI151 to change to CSCI151 directory
     
     
   • copy the file hello.c from you home directory to your CSCI151 directory by typing
     cp ~/hello.c hello.c
     
     
   • type ls to list a contents of a directory
     
     
   • to rename your file type the following
     mv hello.c helloNew.c
     
     
   • type ls to see the changes
     
     
   • to copy the file helloNew.c to the file that has a different name in your CSCI151 type the following
     cp helloNew.c helloCopy.c
     
     
   • type ls to see the changes
     
     
   • to remove the file helloCopy.c type the following:
     rm helloCopy.c and answer y
     
     
   • type ls to see the changes

Part 2

In this part we will continue to practice to use emacs editor and we will write the C program that uses standard library function scanf to obtain two integers typed by a user at the keyboard, computes the sum of these values, and prints the result using printf

• Here is the C program that you should type in file AddTwoNum.c:

  /* My second C program is Addition Program
  input: two integers
  output: sum of two integers */

  #include < stdio.h>

  /* function main begins program execution*/

  int main()
  {

  int num1;    /* first number to be input by user */
  int num2;   /* second number to be input by user */
  int sum;    /* variable in which sum will be stored */

  printf ( "enter first integer\n" );   /* prompt */
  scanf ( "%d", &num1 );             /* read an integer */

  printf ( "enter second integer\n" );   /* prompt */
  scanf ( "%d", &num2 );                 /* read an integer */

  sum = num1 + num2;   /* assign total to sum */

  printf ( "Sum is %d\n", sum );   /* print sum */

  return 0;

  }

  Compile this program.

  Run this program with different input values and observe the output values.