Central Processing Unit Main Memory Monitor Disk Keyboard mouse What's a Computer? Network CPU: (stupid) brain of the computer can do very simple tasks VERY FAST add, write in memory... Goal: Perform elaborate tasks by putting together many simple tasks HOW ? 142 A-1

To solve a specific problem: weather forecast, payroll, word processing, traffic lights A-2 But A computer only understands instructions written as a series of 0’s and 1’s Need a compiler to translate our program into 0’s and 1’s High level language close (but  ) to plain English BETTER What MSVC does for us MACHINE LANGUAGE Could write as such, TIME CONSUMING... Write a program!

142 A-3 Examples of High level languages: What we will use WIDESPREAD A NECESSARY STEP TOWARDS C++, Java... BUT You will learn programming C is not the point A useful skill valid for any language Which language? FORTRAN, LISP… 50’s (scientific) COBOL… 60’s (business) BASIC, PASCAL, C… 70’s (multipurpose) C++…80’s (OOP) Java, Java++… 90’s (platform independent)

142 A-4 Clearly specify the problem Analyze the problem Find an algorithm to solve the problem Logical series of tasks Example: Managing a traffic light Long enough? Change the light Check the time How long has it been since the light has changed? Yes No Write the program (use C). DOCUMENTATION Test and Debug (correct mistakes) Maintain and Update How to write a program

142 A-5 Computers have improved dramatically Still Advancing Pentium has 7.5 millions of transistors 300 millions in 10 years Should level off (?) in 20 years Atom is the limit (insulators are a few atoms thick) A little bit of history a Cadillac would cost $ to 60 mph in 3 milliseconds Go to the moon and back on a tank of gas Could put the Cadillac in your pocket Moore’s Law: every 18 months, double the number of components on a chip... for the same price If the same had happened to cars:

142 A-6 Programming is FUN * * and sometimes frustrating Read the book Come to class Get a lot of practice on the computers And... DO NOT FALL BEHIND Rewards: plenty Open doors in Education: Engineering, Computer Science, Physics, Bio technologies... Employment: e.g. from ADOBE What to Expect? _ Education: None _ Experience: 3 years C++ _ Salary: $96,000

142 A-7 What Car makers say if cars were like computers For no reason whatsoever your car would crash twice a day. Every time they repainted the lines on the road you would have to buy a new car. Occasionally your car would die on the freeway for no reason, and you would just accept this, restart and drive on. Occasionally for no reason whatsoever, your car would lock you out and refuse to let you in until you simultaneously lifted the door handle, turned the key, and grabbed hold of the radio antenna The airbag system would say "Are you sure?" before going off.