2.2 programming

2.2 programming

1. variables, inputs, outputs and assignment

   • programs accept inputs from the user
     • processes it using constants and outputs to user
   • we can label various inputs and constants
     • this is known as assignment
       • information is stored in locations called 'identifiers'
   • it is called a 'variable' if it changes throughout the program
     • allow programs to have different purposes
   • but a 'constant' if it doesn't change
   • any information that a program makes use of is stored in RAM
     • RAM is divided in memory locations with long hexadecimal addresses
   • example of a computer processing an input:
     • input - people getting on bus
       • processing - bus moving along route
         • output - people getting off the bus for work

2. variables : operators

   • Boolean - AND, OR, NOT
     • AND - two conditions must be true for statement to be true
     • OR - at least one of the values has to be correct
     • NOT - inverts the results
   • addition
   • subtraction
   • division
   • left
   • mid
   • right
   • modular division - how many times a number can go into another with a remainder
     • integer division ignores the remainder

3. iteration

   • while
   • for
   • counter
   • condition
   • boolean
   • iteration
   • break
   • nested iteration

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

   • String handling: to get the length of the string, to get a substring, the string will start with the 0th character, ascii conversion
   • Procedure: are sets of instructions stored under one name
   • Functions: are similar to procedures but always return a value to the main program.
   • SQL- Standard Query Language