Scripting Classroom Series – 09/Nov/2019

Basic Program Components (Internal)

Program Conversions into Machine Language

1. Compiler
2. Interpreter
3. Hybrid: Compiler + Interpreter

In which order does Programs Execute your code.

• Any program executes your code sequentially (statement by statement)

python add two numbers

f1 = 10
f2 = 20
result = f1+f2
print(result)

• If you execute this program execution happens sequentially.
• Manually executing Programs is called as debugging.

Scenarios

print all the even numbers below 1000

• Note:

  • Datatypes: integer and boolean
  • Operators: + – * / % = == < >

• Solution 1

integer index = 1
integer max = 1000
repeat till index < 1000
  is index%2 == 0
    print index
  index = index + 1

• Solution 2

integer index = 1
integer max = 1000
integer start = 2 
repeat till start * index < max
  print start * index
  index = index+1

• Convert into Python
  • Find the equivalent operators
  • Find the equivalent data types
  • Find the python syntax

Conditional Statements

• Skipping some statements when conditions are (not) met
• IF Statement

IF boolean expression THEN
 block begin
   statement 1
   ..
   ..
   Statement n
 block end

• IF ELSE

IF boolean expression THEN
 true_block begin
   statement 1
   ..
   ..
   Statement n
 true_block end
ELSE
  false_block begin
   statement 1
   ..
   ..
   Statement n
  false_block end

• CASE/Switch

 CASE(Expression):
   case A:
      A_block begin
      ...
      ...
      A_block end
    ...
    ...
    ...
    default:
       default block begin
       ...
       ...
       default block end

Looping Statement

• Repeating some line when conditions are (not) met
• WHILE

WHILE (Boolean expression)
  TRUE-Block Begins
    Statement 1
    ..
    ..
    Statement n
  TRUE Block Ends

• FOR
• FOR EACH

Python Environment Setup

1. Install Visual Studio Code from here
2. Install python from here