Problem Solving Techniques Using Pascal Allen C.-H. Wu Department of Computer Science Tsing Hua University Hsinchu, Taiwan 30043, ROC

Chapter 1 Overview Of Computers and Programming

Overview Computer Do as I told you! HOW? ChipsProgram SoftwareHardware

A Computer System Central Processor Unit (CPU) Keyboard Mouse Main memory Hard/floppy disks Tape driver Monitor Printer Plotter Inputs Outputs

Interactions between the Users and Computer l The user develops a program. l The computer fetches the program and data through the input devices and stores them in the main memory. l The data then be accessed and manipulated by the CPU. l Finally, the results of this manipulation are fed back to the user via the output devices.

Analogy to Human Systems l A man/woman see a simple arithmetic problem (e.g., 1+1=?) from the blackboard. => Eyes are the input device. l He/she stores the data into his/her brain. => Brain cell ~ memory cell. l His/her brain computes 1+1 and stores the result of 2 into the brain cell. l Finally, he/she tells you or writes down the answer. => Mouth is the output device.

Anatomy of Memory l Address and contents of a memory cell. l Stored program concept. l Bytes and bits. l Storage and retrieve of information in memory. l Main memory (RAM and ROM). l Secondary memory and storage devices.

CPU and IO Devices l The CPU has two roles: (1) coordinating all computer operations and (2) performing arithmetic and logical operations on data. l The CPU retrieves the instruction stored in memory in sequence. l IO devices communicates users and computers. l Computer networks and file servers.

Human, Computer, Problem Solving HumanProblem Describe or formulate Language, program Computer Solve Solution

Programming Strategy l Plan your program solution. l Desk check your solution plan (make changes to your solution). l Write out your program. l Desk check your program (makes changes to your program). l Enter the program into the computer.

Overview of Programming Languages l Programming languages => Programs. l Machine languages => string of 0s and 1s => understand by the computer. l High-level languages => everyday languages => understand by the users. l Language standard => grammar (syntax & semantics). l Source program => object program.

Processing a High-Level Language Program l Editing a program. l Compiling the program - syntax error checking. l Linking and loading the object program and storing it in the memory for execution. l Preparing the input file, executing the program, and output the results.

Turbo Pascal l Two common used operating systems (OS): Microsoft Disk Operating System (DOS) and Microsoft Windows (Windows).