unit 2.2 programming

unit 2.2 programming

1. A memory location where information relevant to the program is called: 'a variable' if it changes throughout the program or, 'a constant' if it is fixed for the duration of the program

2. Variables are from which we build up our programs: whole numbers, real numbers, string, boolean

3. RAM is divided in memory locations with long hexadecimal

4. Constants: are values that don't change as the program runs

5. Analogy with spreadsheets : a grid of memory locations(cells) can hold values . Each cell has an address/label and holds a value or a reference to another address

6. Computers are general purpose problem solving machines, they need: raw materials(inputs), time and instructions to process the inputs, the results(outputs)

7. Variable: memory location with a descriptive label

8. Operators: represent the operations that are performed on the data + - / * ^

9. Pseudocode for string operations: convert a string to UPPERCASE. convert a string to lowercase. length of a string. substring

10. ARITHMETIC OPERATORS: + Addition - Subtracion * Multiplication / Division MOD modulus DIV Quotient ^ Exponentiation

11. COMPARISON OPERATORS: == equal to != not equal to < less than <=less than or equal to > greater than >= greater or equal to

12. 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- start at the top and finish at the bottom

13. Disadvantages of sequencing: not at all efficient. Becomes very difficult to follow with large programs. Extremely hard to maintain.

14. Text files are used to store a variety of data: lists of names, logs of events, tables of data

15. String handling: to get the length of the string, to get a substring, the string will start with the 0th character, ascii conversion

16. Tabulation- the process of writing data to a table is known as tabulation

17. SQL- Standard Query Language

18. Nested select refers to multi-stage filtering.Limitations of the nested select: no sorting allowed. must be in ( ). can only return one column usually. should only return one row

19. Array is an ordered collection of related data where each element is accessible by a number(index)

20. Sub programs can be used to save time and simplify code. The main types of sub programs are procedures and functions.

21. Procedure: are sets of instructions stored under one name

22. Functions: are similar to procedures but always return a value to the main program.