The document contains a C++ program demonstrating subnetting by calculating subnet masks, the number of subnets, and the number of hosts per subnet based on user input. It prompts the user for the network prefix and borrowed bits, then outputs the corresponding subnet mask and calculated values. The example execution shows a subnet mask of 255.255.255.254, one subnet, and an invalid number of hosts due to erroneous input.

1. Practical No:4
Title:Write a program to demonstrate Sub-netting and find subnet masks
Program:
#include <iostream>
#include <cmath>
#include <bitset>
using namespace std;
void calculateSubnetMask(int subnetBits) {
unsigned int mask = 0xFFFFFFFF << (32 - subnetBits);
cout << "Subnet Mask: ";
for (int i = 0; i < 4; ++i)
{
cout << ((mask >> (24 - i * 8)) & 0xFF);
if (i < 3) cout << ".";
}
cout << endl;
}
void calculateSubnets(int borrowedBits) {
int numSubnets = pow(2, borrowedBits);
cout << "Number of subnets: " << numSubnets << endl;
}
void calculateHosts(int hostBits) {
int numHosts = pow(2, hostBits) - 2; // Minus 2 for network and broadcast address
cout << "Number of hosts per subnet: " << numHosts << endl;
}
int main() {
int subnetBits, borrowedBits, hostBits;
int classPrefix;
cout << "Enter the number of bits for the network prefix (e.g., 24 for Class C): ";
cin >> classPrefix;
cout << "Enter the number of bits borrowed for subnetting: ";
cin >> borrowedBits;
subnetBits = classPrefix + borrowedBits;
hostBits = 32 - subnetBits;
calculateSubnetMask(subnetBits);
calculateSubnets(borrowedBits);
calculateHosts(hostBits);
return 0;
}

2. Output:
Enter the number of bits for the network prefix : 255.255.255.224
Enter the number of bits borrowed for subnetting: Subnet Mask: 255.255.255.254
Number of subnets: 1
Number of hosts per subnet: -2
=== Code Execution Successful ===