2.2 Programming

2.2 Programming

1. KEY WORD

   • Input, Output, Assignment, Psuedocode, Flowchart, Identifier, Variable, Constant, Concatenation, Memory Location, Parameters

2. INPUT

   • Inputs come from the console, from a file, or from elsewhere in a modular program – then they are known as 'parameters'

3. OPERATORS

4. Numbers: addition, subtraction, division, modular division (division with a remainder), integer division, multiplication, to-the-power-of, negation Boolean: AND, OR, NOT, larger, smaller, equal, not equal Strings/characters: slicing, length, format

5. INTEGERS AND REALS

   • Addition total = amount + VAT Subtraction e.g. age = cur_year – y_birth Division divide = 5 / 2 Modular division myRemainder = 5 MOD 2 (find a remainder) Integer division intDivision = 5 DVI 2 Multiplication totalCost = cost * 0.2 Exponential area = 3.1 * radius^2

6. STRING OPERATIONS

   • String Features Slicing e.g. LEFT(“monkey”,4) is “monk” Length e.g. LEN(“monkey”) [=6] Change case e.g. “monkey””MONKEY””Monkey” Formatting Features ASCII and Unicode e.g. ASCII(“c”) [=99] Escape characters e.g. ‘it\’s me’ [it’s me] White space: CR NewLine, TAB 4 or 5 spaces

7. BOOLEAN OPERATORS

   • AND - two conditions must be true for the statement to be true OR - at least one condition must be true for the statement to be true NOT – inverts the result, e.g. NOT(A and B) will only be false when both A and B are true

8. WHAT, OPERATORS ARE USED WHERE?

   • Numbers: addition, subtraction, division, modular division (division with a remainder), integer division, multiplication, to-the-power-of, negation Boolean: AND, OR, NOT, larger, smaller, equal, not equal Strings/characters: slicing, length, format
     • EOL
       • EOL means end of line

9. MORE KEY WORDS

   • Sequence, algorithm, Instructions, Efficiency, Structured

10. BENEFITS OF SEQUENCING

    • Each line follows the next Create simple programs very quickly Easy to follow for a small program Fundamental principal of a program

11. DISADVANTAGES OF SEQUENCING

    • Not at all efficient Becomes very difficult to follow with large programs Extremely hard to maintain

12. KEY WORDS

    • IF, ELSIF, ELSE, SELECTION CASE, Boolean, nested, selection, condition, criteria, true, false

13. NESTED SELECTION

    • Sometimes, we can only evaluate a condition if some pre condition is met. We would need two selection statements on inside the other.

14. BIG PICTURE

    • Computers are good at performing

15. EOF

    • EOF means end of file

16. SQL

    • SELECT(fields) . FROM(files) . WHERE

17. BOOLEAN

    • Boolean can only have two values, example TRUE or FALSE...

18. FILE MODE

    • A file can open in either READ or WRITE modes.