Network Subnet Calculator

A robust, command-line-based Java utility designed to simplify IPv4 subnetting calculations, CIDR conversions, and network address validation.

The project uses a structured package layout (Project.tuts):

Network_Subnet_Calculator/
│
├── bin/                      # Compiled class files directory
└── Project/
    └── tuts/
        ├── Main.java         # CLI interface and user input handling
        ├── NetCalculator.java# Core subnet math and network logic
        ├── ip_inclusion.trial
        ├── subnet_algo.trial
        └── progressbar.trial

1. Network Requirement Mode (Mode 1):
   • Takes a desired number of subnets, calculates the required subnet bits, derives the new CIDR notation, and computes total IPs and usable hosts per subnet.
2. Host Requirement Mode (Mode 2):
   • With IP Validation: Supports Class B (172.16.xx.xx) and Class C (192.168.xx.xx) networks. Validates whether an entered network address aligns with the given CIDR mask before calculating ranges.
   • Without IP: Calculates required host bits, total block size, usable host counts ($2^h - 2$), CIDR prefix, and subnet masks based strictly on host demand.
3. Robust Input Handling:
   • Gracefully manages menu validation and prevents infinite loops on invalid or non-integer inputs.

Since the repository includes trial files alongside the core source code, you only need to compile Main.java and NetCalculator.java.

Open your terminal in the root repository directory and run:

javac -d bin Project/tuts/Main.java Project/tuts/NetCalculator.java

Execute the compiled main class using the classpath flag:

java -cp bin Project.tuts.Main