Programming

Approach

• Programs dont respond to make tea rather they expect instructions
• These instructions or the way we represent these instructions is referred as programming logic or algo etc.
• Note:
  • Never Write Program with out instructions
  • Programs fail
• Principle: Programming is 80% debugging and 20% writing
• Lets instruct chaitra
  
• Chaitra knows + -
• Sample instruction

Hi chaitra
say 5 + 6

• Sample Response

11

• Sample Instruction

Hi Chaitra
remember 90 as maths
remember 80 as science
say maths + science

• Sample Response

170

• Write instructions for chaitra to calculate 3 * any number. Chaitra knows + -

Hello Chaitra
Remember 2 as number
say number + number + number

• Chaitra now knows + - * / // % ==
• Write instructions for chaitra to say if the number is even

Hello Chaitra
Remember 6 as number
calculate number %2 and remember as result
say even if result == 0

• Moral of story sofar
  • Learn to write instructions
  • Examine Instructions (debugging)

How Programs are Executed on a System

• Typically we run our program on Operating Systems.
• Operating System allows us to
  • run custom applications
  • allows application to interacts with hardware with an abstracted interface
• Operating Systems creates a Process with a unique id, some ram & cpu allocated to it
• CPU w.r.t your program executes instructions and RAM stores values

Memory in RAM

• Data Types: The basic idea of data type is to allocate memory in a way convinient to developers.
  • Size
  • nature:
    • static size (mutable types)
    • dynamic size (immutable types)