A file "parts_inv.dat" contains on each line a part number, cost, and quantity in inventory, in the following format: 123 5.99 52. Use fgetl to read from the file and form a matrix "partsmat." Then, store the total dollar amount of the inventory (the sum of the cost multiplied by the quantity for each part) in the variable "total_amount". You do not need to error-check the file open or close.