Software 1 - Administrivia & simple programs (1)

Administrivia

Practice Web Page - http://www.cs.tau.ac.il/~efif/courses/Software1_Spring_04

Overview of the course

• C programming
• Unix programming - C shell - basic unix commands
• C++ programming - introduction, maybe.

Homework

• An assignment every two weeks
• Singleton submission
• Assignments are worth 20-25% of total grade
  • Final exam is worth 80-75%

Homework Issues

• You can use your home computer
• You can use your friend’s computer
• You can use any computer you like
• But the programs you submit must work on Linux
  • Preferably on the Unix system in the lab.
  • Use any of the options above at your own risk
• See Submission Guidelines for precise instructions

  • /* .....
     * Full Name: your-full-name
     * Id No: your-id
     * User Name: your-user-name
     * Group No: your-group-number
     * Assignment No: the-assignment-number
     * .....
     */
    

Working from home at your own risk

• Develop the code with the available tools
• Copy the files that contain the source code later to the university
• Compile again at the univerisy to verify that everything works

Account, labs, printing, email, etc.

• If you don't have an account on the Unix system, you need to open one.
  • You are advised to open an account on the Sigma (windows) system while you are at it.
• If you have an account, make sure to change your password

  passwd

• All sorts of useful information can be found at the system FAQ http://www.cs.tau.ac.il/faq
  • For example, list of printers and instructions system FAQ for printing
• All issues will be covvered next week during the hands-on sessions.

Hands-on session

• Where: Schreiber 04 - one of the computer labs. in the Computer Science school
• When: Mon., Tue., and Wed. between 15:00 - 17:00
• Content
  • Developing at home
    • locally - on a local machine
    • remotely - on a university machine
  • Developing on Linux and windows
  • Copying Files and accessing the Unix computers in CS

Basic model

Terminology

• bit: binary digit
• byte: a group of 8 bits. Can represent 256 values (0 to 255 or -128 to 127).
• nibble (obsolete): half a byte
• word: a group of bytes that a specific computer is optimized for working with (usually 4 or 8)
• kilobyte (K or KB): 1,000 bytes, or sometimes 1,024 bytes (2¹⁰)
• megabyte (M or MB): 1,000,000 bytes, or sometimes 1,028,576 bytes (2²⁰)

Computer languages

• Assembly
  • essentially just machine language with some text codes
• Compiled languages
  • converted into machine language before use
  • examples: C, Pascal, Fortran
• Interpreted languages
  • converted into machine language during use by an interpreter
  • examples: Basic, Perl, (Java)
• Most languages were designed with one or the other mechanism in mind
  • but there are interpreters for C, and there are compilers for BASIC
  

The whole process

• Write a program
  • Text editor
• Compile the program
  • C compiler
  • will do one of two things:
    • print error messages and abort
    • produce an executable program
• Run the program

Example - hellow

• A program that print "Hello World" to the standard output (terminal)

  #include <stdio.h> int main(void) { printf("Hello World\n"); return 0; }

• hellow.c
• Compiling using the commands line interface

  gcc -Wall hello.c -o hello hello

Convert Fahrenheit to Celsius

• A program that converts Fahrenheit to Celsius

  #include <stdio.h> int main() { float fahr; float celsius; scanf("%f", &fahr); celsius = 5 * (fahr - 32) / 9; printf("Fahrenheit = %.2f, Celsius = %.2f\n", fahr, celsius); }

• fahren.c