Learn Ruby Language and Be an exploit coder-3

Numbers And Math

Ain't it boring? well i promise that u guyz will enjot next article but u must have to learn basics first.

Lets move to our tutorial.

Every programming language has some kind of way of doing numbers and math. Do not worry, programmers lie frequently about being math geniuses when they really aren't. If they were math geniuses, they would be doing math, not writing ads and social network games to steal people's money.

This exercise has lots of math symbols. Let's name them right away so you know what they are called. As you type this one in, say the names. When saying them feels boring you can stop saying them. Here are the names:

• + plus
• - minus
• / slash
• * asterisk
• % percent
• < less-than
• > greater-than
• <= less-than-equal
• >= greater-than-equal

Notice how the operations are missing? After you type in the code for this exercise, go back and figure out what each of these does and complete the table. For example, + does addition.

• puts "I will now count my chickens:"
• 
  
• puts "Hens", 25 + 30 / 6
• puts "Roosters", 100 - 25 * 3 % 4
• 
  
• puts "Now I will count the eggs:"
• 
  
• puts 3 + 2 + 1 - 5 + 4 % 2 - 1 / 4 + 6
• 
  
• puts "Is it true that 3 + 2 < 5 - 7?"
• 
  
• puts 3 + 2 < 5 - 7
• 
  
• puts "What is 3 + 2?", 3 + 2
• puts "What is 5 - 7?", 5 - 7
• 
  
• puts "Oh, that's why it's false."
• 
  
• puts "How about some more."
• 
  
• puts "Is it greater?", 5 > -2
• puts "Is it greater or equal?", 5 >= -2
• puts "Is it less or equal?", 5 <= -2

What You Should See :

• $ ruby exploit3.rb
• I will now count my chickens:
• Hens
• 30
• Roosters
• 97
• Now I will count the eggs:
• 7
• Is it true that 3 + 2 < 5 - 7?
• false
• What is 3 + 2?
• 5
• What is 5 - 7?
• -2
• Oh, that's why it's false.
• How about some more.
• Is it greater?
• true
• Is it greater or equal?
• true
• Is it less or equal?
• false
• $

Extra Credit.

Above each line, use the # to write a comment to yourself explaining what the line does.
Remember in First Lecture when you started IRB? Start IRB this way again and using the above characters and what you know, use Ruby as a calculator.
Find something you need to calculate and write a new .rb file that does it.
Notice the math seems "wrong"? There are no fractions, only whole numbers. Find out why by researching what a "floating point" number is.
Rewrite exploit3.rb to use floating point numbers so it's more accurate (hint: 20.0 is floating point).