Q4: Write a C# program that has a Main method and a user-defined method called ComputeTax. The
Main method asks the user to enter an item's cost (double) and the percentage sales tax (double).
The item cost is a positive number and the percentage sales tax is a number between 0.0 and 1.0.
Main then calls the method named ComputeTax which has two parameters that will hold the
item's cost and percentage sales tax as arguments. The method returns the overall price of the
item (double) which should be output by Main. For example, if an item's cost is $3.50 and
percentage sales tax is 10% (entered as 0.1), then the value returned by the ComputeTax (and
printed by Main) is $3.85. The method header for ComputeTax should look like:
public static double ComputeTax (double itemCost, double perTax)
**** Note: On this assignment you can assume the correct datatype: that is, if the program requests
a double, you can assume that the user will input a double, etc. You do need to check that the data
is in the correct range.