2.2 programming

2.2 programming

1. variable

   • Computer programs accept inputs from a user, process them using some constants and output back to the user. It is a good idea to label various inputs, constants and outputs with descriptive names (the process known as assignment).
   • keywords
     • input ;output; assignment ;pseudo code ;flowchart ;identifier; variable ;constant ;concatenation ;memory locations ;parameters

2. operators

   • 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
   • keywords
     • addition-subtraction-division-negation modular division-integer division and-or-not-greater than-less than equal-not equal-Arithmetic-Boolean-string-concatenate sub string-delimiter-split-left-mid-right modulus-quotient-exponentiation

3. sequencing

   • Sequencing allows a programmer to solve complex tasks through a number of simple steps. The order of steps in most tasks matters – similarly, we use brackets in math to make sure that certain operations are done before others (sometimes we need to add before we do multiplication and division).
   • advantages and disadvantages of sequences
     • advantages: each line follows the next ; create simple program;Easy to follow for a small program;Fundamental principal of a program; - Starts at the top, finishes at the bottom disadvantages: Not at all efficient; becomes very difficult to follow with large programs ;Extremely hard to maintain
   • keywords
     • Sequence/algorithm Instructions; Efficiency; Structured

4. selection

   • The use of selection allows a computer to “think” – make decisions Selection changes the flow of a program, depending on a set of conditions, it is used for validation, calculation and making sense of a user’s choices. Good connection to the topic of Boolean operations and logic gates
   • keywords
     • IF ;ELSE IF ;ELSE SELECT CASE ;Boolean Nested ;Selection; Condition ;Criteria; True ;False
   • nested selction
     • Sometimes, we can only evaluate a condition if some pre-condition is met. We would need two selection statements, one inside the other. The “outside” selection is the pre-condition, while the “inside” selection is the condition. There is no limit on how many selection statements we can nest.

5. iteration

   • is a process wherein a set of instructions or structures are repeated in a sequence a specified number of times or until a condition is met. When the first set of instructions is executed again, it is called an iteration.
   • keywords
     • While; For; Counter ;Condition ;Boolean ;Iteration Break; Nested iteration; Exit condition; Stepping; Increment/ Decrement ;Larger/Greater; Greater or Equal; Smaller or Equal

6. file handling

   • text files
     • Text files are used to store a variety of data: Books and business documents Logs of events Lists of names Tables of data with various numbers of columns and rows While a book or a receipt is considered one item of data – used whole (e.g. to search for a word), when we store logs and lists, we have arrays of data, made up of individual elements of different data types.
   • keywords
     • EOF – end of file; EOL – end of line ;New Line Character (CR or Carriage Return) or LineFeed; File mode; Commit ;Append; Overwrite ;Tabulation/Table; Serialise ;Deserialise; Delimiter; Schema

7. string manipulation

   • to string manipulate
     • Extract or truncate the first few characters of a string, Extract or truncate some characters at the end of the string, Find out the length (number of characters) of a string, Convert a string from lowercase to UPPERCASE or vice-versa, Check if a character has been used in a string, Find out if a string contains a specific substring or word,
   • string
     • In computer programming, a string is traditionally a sequence of characters, either as a literal constant or as some kind of variable. The latter may allow its elements to be mutated and the length changed, or it may be fixed (after creation).