Algorithm constructs

Algorithm constructs

1. Sequence

   • A number of instructions that are processed one after the other.
   • Order of steps in code
   • DECLARE count SET count TO 1 OUTPUT the value of count

2. Assignment

   • Used to store the value of an expression into a variable.
   • Assignment is the way that a variable is told to remember a certain value.
   • Declaring a Variable
   • DECLARE studentName SET studentName TO Bob

3. Selection and Condition

   • A selection statement uses a condition to select, or determine, the next line of the program that is to be executed.
   • If, if else
   • CALCULATE totalCost IF (totalCost > $10) THEN OUTPUT   'no delivery charge' ELSE OUTPUT  '$5 delivery charge' ENDIF OUTPUT  'thankyou

4. Iteration

   • Iteration is also called repetition and is used when something is repeated over and over again, so anything where the program goes round in a loop.
   • For loop
     • DECLARE count SET count TO 0 FOR count = 1 to 10 OUTPUT count END FOR OUTPUT ‘finished’
   • While loop
     • DECLARE count SET count TO 0 WHILE (there are items in a pile) ADD 1 TO count  END WHILE OUTPUT the number of items

5. Modularisation

   • Modularisation is used to reduce the complexity of a system by deconstructing it into independent units or modules.
   • FUNCTION delivery_charge CALCULATE totalCost IF (totalCost > $10)  THEN OUTPUT  ‘no delivery charge’ ELSE OUTPUT  ‘$5 delivery charge’ ENDIF OUTPUT  ‘thankyou’ END FUNCTION