Note: This post assume that you have successfully installed Ruby on Rails in your computer.
Ruby as a Calculator
Type following command on your command prompt
irb --simple-prompt
and press "Enter" key from the keyboard. You will received following respond
C:\>irb --simple-prompt
>>
At ">>" command prompt, enter "10+20" and press enter key. You will received following respond
C:\ruby>irb --simple-prompt
>> 10+20
=> 30
>>
A "=>" command prompt symbol showing answer of the "10+20" airthmetic equation. Again ">>" command prompt symbol come so you will use this prompt for new airthmetic equation. Ruby support addition (+), subtraction (-), multiplication (*) and division (/) airthmetic operator. Remaining airthmetic operator I will discuss some time later.
If you want to out of irb then type exit at ">>" command prompt and press "Enter" key from the keyboard.
>>exit
C:\ruby>
In my case I am using these command inside ruby folder at "C" drive, so "C:\>Ruby" prompt comes.
Number Datatypes in Ruby
Try following division arithmetic operator
C:\ruby>irb --simple-prompt
>> 3/2
=> 1
>>
An integer is a whole number, like 3, 6, -5, etc. When you operate using only integers, Ruby will give you an Integer answer. 3/2 is 1.5, but that isn't an integer, so Ruby gives you 1 instead.
But if you try 3.0/2.0 then ? let's try
C:\ruby>irb --simple-prompt
>> 3.0/2.0
=> 1.5
>>
A float is a decimal number, like 3.14, 6.51, 3.0, etc. When you operate using only float, Ruby will give you an float answer. 3.0/2.0 is 1.5
More Arithmetic Operator
Exponent (**)
C:\ruby>irb --simple-prompt
>> 6 ** 2
=> 36
>>
Remainder (%)
C:\ruby>irb --simple-prompt
>> 6 % 4
=> 2
>> 7.1 %2
=> 1.1
>>
Working with Large Number
