1. C Programming for engineers Teaching assistant: Ben Sandbank e-mail:sandban@post.tau.ac.ilsandban@post.tau.ac.il Home page: http://www.cs.tau.ac.il/~sandban http://www.cs.tau.ac.il/~sandban Office hours: Wednesday, 16:00- 17:00, room 19 in the basement of the Schreiber building Office phone: 03-6405378

2. C Programming for engineers Teacher: Amitai Armon Course home page: To be announced

3. Recommended books The C Programming Language (second edition - ANSI C), Brian W. Kernighan and Dennis M. Ritchie, Prentice Hall, Inc., 1988. A Book on C (third or fourth edition), Al Kelley and Ira Pohl, Addison-Wesley, 1997. These and other C programming books can be found in the library under 519.83

4. Homework Weekly homework assignments Each assignment is due in one week The assignments are worth 20% of the final grade. The rest – a written exam. See submission guidelines for details.submission guidelines

5. Homework (cont.) Each assignment – programming problems. Submission in singles. The assignments will be handed in in hard- copy to me during practice or in my box in the Schreiber building (second floor, in front of the elevator). Pay careful attention to the guidelines.

6. What can a computer do? Strictly speaking, very little - Store and retrieve numbers very quickly very accurately Add, subtract, multiply, and divide also fast and accurate Compare numbers (with 0) Follow a list of instructions jump around in the list

7. What about everything else? More complex math Combination of atomic operations Interaction with peripheral devices Output: graphics cards and printers Input: keyboards, mice, joysticks All sorts of specialized devices Everything done using numbers To the computer everything is numbers

8. What numbers does a computer work with? Instructions. Addresses. Data: Integer numbers. Real numbers. Text. All sorts of other things.

9. Data representation inside the computer Bit – a binary digit: 0 or 1. Bits are always grouped! Byte – a group of 8 bits. Therefore, a byte can represent up to 2 8 =256 values. The values can range from 0 to 255 or from -128 to 127. The fundamental data unit of a computer. Word – a group of (usually) 4 (or 8) bytes. 4 bytes = 32 bits. Value range: 0 to 2 32 -1 (4,294,967,295 ). Or, more often: -2 31 to 2 31 -1 (-2,147,483,648 to +2,147,483,647).

10. Inside the computer The computer memory is composed of a long list of bits. Bits are grouped into bytes and words. Every byte is numbered sequentially. This number is called an address.

11. Basic computer model

12. What is a computer program? A sequence of processor instructions designed to achieve a specific purpose The instructions are executed sequentially. No instruction is executed before the previous has been completed. Each instruction has a numerical code.

13. Examples of instructions Load data (from an address in the memory). Store data (in an address). Add two numbers. If two numbers are equal, jump to another part of the program. Instructions are numbers!

14. Machine language Computers understand only machine language. Every processor has its own machine language. Basically looks like a sequence of 1’s and 0’s. Very inconvenient to work with and non intuitive. All other computer languages were created for human convenience The computer does not understand C. Must be converted into machine language.

15. Computer languages (getting closer to human languages) Assembly – machine language with some text codes (still inconvenient). Interpreted languages – Java, Perl. The program is translated into machine language line by line during execution. Compiled languages – C, Pascal, Fortran. The program is translated into machine language before execution

16. High level languages vs. machine languages. Actually, binary instructions.

17. C is a procedural language It enables the user to create new instructions (procedures) from existing ones. Instead of re-writing the same code over and over again, write it once and call it when needed.

18. Why different languages? Many languages were developed with specific applications in mind: Data processing. Web applications. Mathematical calculations. Artificial intelligence.

19. How do we compile? A special program – the “compiler” – “translates” from computer language to machine language. There are many compilers on the market. We will work with Microsoft Visual C++ 6.0.

20. Let's look at the whole process Write a program Your favorite text editor Compile + link the program C compiler will do one of two things: print error messages and abort (most probably…) produce an executable program Run the program

21. This is a comment – starts with a /* and ends with a */. Comments are used to explain the program to a human reader, and are ignored by the compiler. Curly braces indicate the beginning and end of a block of instructions. Specifically in this case – a function. This is an instruction to the compiler to insert the contents of the file stdio.h to the program prior to compilation. This file contains information about the printf fuction. Yet another C statement. This one terminates the program and informs the operating system that it has ended successfully. This tells the compiler we are about to define a function named main. main is a special function – it is where the program starts running. This is a C statement. This statement calls a function called printf, which causes text to be printed on the screen. Note that all C statements end with a semicolon (;). Our first C program /* HelloWorld – An example program */ #include int main(void) { printf(“Hello, world!\n”); return 0; }

22. Now, let’s get to work!!! Help using Microsoft visual c++

23. Exercise Write, compile and run a program that prints your first name in one line, and your second name in another.

24. A name printing program /* This program prints my name on the screen in two lines. */ #include int main(void) { printf(“Ben\nSandbank!\n”); return 0; }

25. C programming for Engineers LCC compiler – a free c compiler available on the web. http://www.cs.virginia.edu/~lcc-win32/ Some instructions