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ENGR2216 FORTRAN PROGRAMMING FOR ENGINEERS

ENGR2216 FORTRAN PROGRAMMING FOR ENGINEERS. Chapter 1. The computer CPU MEMORY INPUT/OUTPUT DEVICES DATA REPRESENTATION BINARY SYSTEM OCTAL & HEXADECIMAL DATA TYPES HISTORY OF FORTRAN EVOLUTION OF FORTRAN. Computers: are they important?. Solving problems in any field

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ENGR2216 FORTRAN PROGRAMMING FOR ENGINEERS

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  1. ENGR2216FORTRAN PROGRAMMINGFOR ENGINEERS

  2. Chapter 1 • The computer • CPU • MEMORY • INPUT/OUTPUT DEVICES • DATA REPRESENTATION • BINARY SYSTEM • OCTAL & HEXADECIMAL • DATA TYPES • HISTORY OF FORTRAN • EVOLUTION OF FORTRAN

  3. Computers: are they important? • Solving problems in any field • Can you imagine a computer without software (programmes)? • Computer’s success is tied to programming

  4. Where do we find computers? • In a grocery store: scanners checking prices • ATM (Automatic Teller Machines) • Mobiles • Microwave oven • Cars • Do you believe that the first electronic computer was invented about 60 years ago?

  5. Basic Definitions • A computer: • is a special type of machine that stores information and can perform mathematical calculations on that information at speeds much faster than human beings can think. • A program: • tells the computer what sequence of calculations are required and on which information to perform the calculations.

  6. Examples of Programmes • A computer at the bank stores customers’ information. • Another programme can check each customer’s account daily. Once it goes below 100 Rials, the customer gets charged 1 Rial. • Another programme can monitor the customers’ account, and send an sms message to the customers informing them that it’s time to take out their Zakat. • Another program: • when your phone’s battery becomes low, it gives you a warning: ”low battery”.

  7. Computers vs. Human • Are computers smarter than human? • No, they only process programmes faster. • They follow the instructions given in a programme. • They can’t think on their own. • They must be told what to do and when to do it • A clever programme means a clever programmer

  8. The computer • CPU = computer’s heart • CPU = Control + ALU + memory • Control: controls all PC parts • ALU: performs calculations • Memory: temporary storage of results during calculations • Control: • Interpret instructions • Fetch data from input • Send data from memory to output devices or main memory • E.g. multiply 2 × 3

  9. The computer • Main memory • (e.g. RAM) • Primary • Volatile • Semiconductor chip • Very fast • Fetch time  60 ns • Expensive • Store currently used programme • Secondary memory • (e.g. HDD) • Non-volatile … explain! • Higher capacity (80GB vs. 1GB) • Slower • Cheaper

  10. The computer • Input devices • Purpose: enter data/information • Examples: • Keyboard • Mouse • Scanner • Camera • microphone • Output devices • Purpose: display results • Examples: • Monitors/ LCDs • Printers • Plotters • speakers

  11. The binary number system (725)10 = 7× 102 + 2 × 101 + 5 × 100 Used by human (101)2 = 1× 22 + 0 × 21 + 1 × 20 Used by computers Examples: Find the following: (111)2 = (……)10 (011)2 = (……)10 (00001110)2 = (……)10 Byte = 8 bits How many possible values can we make with a 3-bit binary number? Hint: (000) to (111) HOW TO CONVERT FROM BASE 10 TO BASE 2? The 2n rule.

  12. Data representation in a computer • What is a computer memory composed of ? • Millions of ON/OFF switches • How does a PC store data in memory? • A switch is either ON (1) or OFF (0) • A single switch can represent only 1 or 0. • What does bit mean? • BIT stands for Binary Digit • A bit is either 1 or 0. • 1 Byte = 8 bits representing a binary number • E.g. memory of 256 MB (megabytes) = 256 million bytes • E.g. hard disk drive with storage of 40 gigabytes = 40 billion bytes • 1 word = 2, 4, (or more) consecutive bytes = 32, 64, bits • How many possible values can we make with 1 byte? • 28 = 256 possible values (-128 to 127)

  13. Binary (2), Octal (8) and Hexadecimal (16)

  14. Types of Data stored in memory • Each type needs a different amount of memory • Character Data: • UPPER CASE LETTERS (A-Z) = 26 • Lower case letters (a – z) = 26 • Digits (0 – 9) = 10 • Symbols: “ , ( ) [ ] ! ~ @ # $ % ^ & * . • Special letters or symbols (e.g. é) • Total number < 256  1 byte per character • 1,000 characters need 1,000 bytes • For non-English languages, more characters are used) • Task: read text book for • ASCII coding and EBCDIC coding • Integer Data • Real Data (floating point)

  15. Types of Data stored in memory • Each type needs a different amount of memory • Character Data • Integer Data: • -ve integers, +ve integers, and zero • Needs 1, 2, 4, or 8 bytes (differs from one computer type to another) • In any computer that uses n-bit integer: • Smallest integer = -2n-1 • Largest integer = 2n-1 – 1 (why -1?) • What happens if a larger number is used? • Task: read text book • Error: Overflow condition • Real Data (floating point)

  16. Types of Data stored in memory • Each type needs a different amount of memory • Character Data • Integer Data • Real Data (floating point): • Used for fractional numbers (e.g. 0.25) • Used for very large or very small integers • Value = mantissa × 2exponent • E.g. speed of light in decimal system = 2.998 × 108 m/s • Computers use base 2 system, with 32 bits (4 bytes) of computer memory: • 24 bits for mantissa • 8 bits for exponent • Task: read text book • Precision • Range • Round-off error

  17. Computer Languages • Machine language • A program is a list of operations to be executed by a computer: • E.g. load, store, add, subtract, etc. • Each operation has a binary pattern (e.g. add = 1011) called op code • The data associated with the op code are called operands • A set of op codes is called machine language • E.g. add 3,4 1011 0011 0100 • store A 0101 0000 1010 • Machine language is very hard for human • High level languages: • Easy to write/understand • List of instructions • Convert to machine language using compilers and linkers • Examples of high level programming languages: • Basic • C++ • COBOL • Fortran • Java

  18. FORTRAN Language • Grandfather of all scientific computer languages • FORmula TRANslation • Translate formula into a computer code • First FORTRAN: 1954 – 1957 By IBM for 704 computers

  19. FORTRAN Language • Grandfather of all scientific computer languages • FORmula TRANslation • Translate formula into a computer code • First FORTRAN: 1954 By IBM for 704 computers • Integers and real data types only • No subroutines • FORTRAN II: 1958 • FORTRAN IV: 1962 (stayed for 15 Years) • FORTRAN IV: 1966 (adopted as ANSI standard, and called FORTRAN 66 • FORTRAN 77: 1977 (introduced IF statements, and simplified using characters) • Fortran 90: 1992 • Fortran 95: 1996 • Text book covers both 90/95 • Task: • Read sections 1.4, and 1.5 of the text book

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