2.2 programming

2.2 programming

1. what are variables

   • 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).
       • none of them should start with a number or contain spaces
         • input name-------- phrase="i like you + name ----- output phrase

2. during assignment , information is stored in memory locations under descriptive names called "identifiers"

   • a memory location where information relevant to the program running is stored called :"a variable if it changes throughout the program or a constant" if it is fixed for the duration of the program
   • variables come in different types, like different containers for different purposes in real life
     • example petrol is different to a jug of milk

3. key words

   • input and output
   • assignment
     • pseudocode
   • flowchart
     • identifier
   • variable
     • constant
       • memory locations
         • parameters

4. operators

   • when you get the information for the inputs or "HARD - CODED " (typed in when designing) in the program we need to manipulate this data - calculate, compare
     • operators represent the operations that are performed on the data
       • operators in math's : +,-,/,*,^ ect.
         • without operators and correct order for calculations , we can get into a mess. you need strict rules to ensure the results are as intended
           • scratch covers most of the operators
   • key words
     • arithmetic
     • boolean
       • Boolean operators are often taught via a murder mystery where a suspect has to identify a certain set of criteria ( this can reference the popular board game cluedo )
     • string
     • concatenate (join)
     • substring
     • delimeter
     • split
     • left
     • mind
     • modular division
     • addition
     • subtraction
     • division
     • integer divison
     • negation
     • 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,b) will only be false when both A and B are true
     • greater than and greaterless
     • equal and not equal
     • modulus
     • quotient
     • exponentiation
   • Bodmas= brackets , orders , divison , multiplication, addition