### How the programs are executed

• Interpreter/Compiler will read the program and execute it statement by statement
• Lets look at the following section
``````1. Take input
2. check if the input is even
3. print input is even
4. print input is odd
``````
• If we consider the above statements
• for even number 1,2,3 lines/statement should be executed
• for odd number 1,2,4 should be executed
• To solve this in programming languages we have conditional statements which help in selecting the lines/statements valid for the input provided
``````1. Take input
2. if input is even
3. then print input is even
4. else print input is odd
``````
• Lets look of following section
``````1. Take input from user (date)
2. if date is b/w march and june
3. print summer
4. else if date is b/w july and october
5. print rainy
6. else
7. print winter
``````
• Looping constructs:

• Lets assume we need to solve Print all the even numbers from 10 to 100
• not a solution:
``````print 10
print 12
print 14
print 16
...
...
``````
• solution:
``````index = 10
repeat till index <= 100
if index is even
print index
index = index + 1
``````
• Is palindrome for Jarvis

``````Hi Jarvis remember the steps
Take input from user and call it a number
Jarvis can you find reverse of number and remember as reverse
if reverse is equal to number
say palindrome
else
say not a palindrome
``````
• A Brute force approach:
``````Hi Jarvis Help me out
first = 100
second = 100
max_value = 999
max_palindrome = 0
repeat till first <= max_value
repeat till second <= max_value
number = first * second
Jarvis check if the number is palindrome
if palindrome and number > max_palindrome
max_palindrome = number
``````

#### Project Euler problem 5

• Refer Here
• The number should be divisible by all the numbers from 1 to 20
• Solution
``````Hi Jarvis,
max_factor = 1*2*3*4......20
repeat from 20 till max_factor
is_divisible_by_all = True
repeat index from 1 till 20:
if number is not divisible index
break,
increment number by 20
``````

### Exercise: Project Euler Problem 6

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