Programming

Overview

How lisa understands your recipe

• lisa remembers values when you give some name to it

Remember 1000 as amount
or
amount = 1000

• lisa executes the instructions in a step by step order

1. instrcution 1
2. instruction 2

• lisa knowledge

* multiply
+ add
/ division
% modulus or remainder
- subtraction
== equals
!= not equals
< <= >= >
= assignment

• we can store the result of operation as shown below

gst = (amount * 18 / 100)
Calculate (amount * 18 / 100) and store into gst

Problem 1:

• Statement: I want lisa to calculate if the year is leap or not
• Simple version: if the year is divisible by 4

1. Remember 1996 as year
2. calculate year % 4 and store in result
3. if result == 0 say leap year

• Actual version
  • if number is divisible 4 but not by 100 its a leap year
  • if the number is divisible by 4 and also by 100 it should be divisible by 400 to be a leap year
• Solution

1. Remember 1900 as year
2. is_divisible_by_4 = year % 4
3. is_divisible_by_100 = year % 100
4. is_divisible_by_400  = year % 400
5. if is_divisible_by_4 == 0 
5.1    if  is_divisible_by_100 == 0
5.1.1       if is_divisible_by_400 == 0 then say leap year
5.2    else is_divisible_by_100 != 0 then say leap year

Problem 2:

• Make lisa tell if the number is pallendrome or not
• lisa knowledge

* multiply
+ add
/ division
% modulus or remainder
- subtraction
== equals
!= not equals
< <= >= >
= assignment

• Solution

1. number = 153
2. actual_number = number
3. reverse_number = 0
4. remainder = number % 10 
5. number = number / 10  
6. reverse_number = (reverse_number * 10) + remainder
7. if number != 0 goto step 4
8 if actual_number == reverse_number say pallendrome
9. else say not a pallendrome

Problem 3:

• Fibonnaci series

1,2,3,5,8,13,21,34,55,89......

• Make lisa say all the fibonnaci series numbers below 50
• lisa knowledge

* multiply
+ add
/ division
% modulus or remainder
- subtraction
== equals
!= not equals
< <= >= >
= assignment

• Solution

1. first_number = 1
2. second_number = 2
3. say first_number
4. say second_number
5. result = first_number + second_number
6. say result
7. first_number = second_number
8. second_number = result
9. if result < 50 then go to step 5

Programming Concept

• Every process has its own CPU cycles and memory which is private to it
• To reuse functionality
  • use packages or libraries