Simple program to get a custom subnet mask, made in COBOL (work in progress) Features:
-Tell the user which class of network the supplied would fall under (A,B,C,D,E)
-Outputting the default subnet mask of that the supplied IP would use
-Calcuate a custom subnet mask based on the amount of desired hosts and desired amount of subnets
-Basic error handling to prevent impossible networks (i.e. trying to get it to create subnet mask for a class C network with over 254 hosts)