Ruby - Number Numbers
Introduction
To calculate the selling price or grand total of some item based on its pretax value or subtotal.
Demo
subtotal = 100.00 taxrate = 0.175 # w ww . j av a2 s. co m tax = subtotal * taxrate puts "Tax on $#{subtotal} is $#{tax}, so grand total is $#{subtotal+tax}"
Result
Here is a simple calculator that prompts the user to enter a subtotal:
Demo
taxrate = 0.175 print "Enter price (ex tax): " s = gets # ww w.j a va 2 s .com subtotal = s.to_f tax = subtotal * taxrate puts "Tax on $#{subtotal} is $#{tax}, so grand total is $#{subtotal+tax}"
Result
Here s.to_f is a method of the String class.
It converts the string to a floating-point number.
For example, the string "145.45" would be converted to the floating-point number 145.45.
If the string cannot be converted, 0.0 is returned. For instance, "Hello world".to_f would return 0.0.