Practical D

1. Re-write the programme of Examples 19 and 21 from Practical C so that the function is in a header file. Compile and run it.
   
   
2. Modify the stock control programme from "above" to include a field in the struct for the supplier of each item and a line in the main function to set it (to Josephine Bloggs Ltd, perhaps).
   
   Add some code which checks the number of hammers in stock and prints out some text suggesting that an order should be placed with the supplier if this number is below a given critical value.