Program to find Class, Broadcast and Network addresses

20 Jan, 2022
Prerequisite – Introduction and Classful Addressing, Classless Addressing Given a valid IPv4 address in the form of a string. The task is to determine the class of the given IPv4 address as well as separate Network and Host ID parts from it.IPv4 address: Every host and router on the internet has an IP address that encodes its network number and host number, a combination of the two is unique. An IP address does not actually refer to a host but refers to a network interface, so if the host is on two networks, it must have two IP addresses.Default Mask: An address mask determines which portion of an IP address represents network number and which part represents host number, e.g., IP address, the mask has four octets. If a given bit of the mask is 1, the corresponding bit of the IP address is the in-network portion and if the given bit of the mask is 0, the corresponding bit of the IP address is in the host portion. 
CIDR: Classless Inter-Domain Routing uses slash(/) notation to specify the mask with IPv4 address. The address is given as x.y.z.t/n where x.y.z.t is the IP address and n is the number of 1’s in the default mask.Network address: The first address of a network is a network address. It is obtained by ANDing the mask with the IP address (Both in binary form). Another method is to set the last 32-n bits of the IP address to 0.Broadcast address: The last address of a network is a broadcast address. It is obtained by ORing the complement mask with the IP address(Both in binary form). Another method is to set the last 32-n bits of the IP address to 1.Class: The class of an address is identified by the first byte of the address. There are currently five classes A, B, C, D, and E. The range of the first byte of each class is: 
Class A: 0 - 127
Class B: 128 - 191
Class C: 192 - 223
Class D: 224 - 239
Class E: 240 - 255 
Example-1: 
CIDR: 192.168.32.1/24(x.y.z.t/n)
IP Address(Binary):  11000000101010000010000000000001
Default Mask(Binary):  11111111111111111111111100000000
Default Mask: 255.255.255.0

32-n=32-24=8  

First Address: Set last 8 bits of IP address to 0
              = 11000000101010000010000000000000
              = 192.168.32.0

Last Address: Set last 8 bits of IP address to 1
              = 11000000101010000010000011111111
              = 192.168.32.255  
Example-2: 
CIDR: 205.15.37.39/28(x.y.z.t/n)
IP Address(Binary):  11001101000011110010010100100111
Default Mask(Binary):  11111111111111111111111111110000
Default Mask: 255.255.255.240

32-n=32-28=4  

First Address: Set last 4 bits of IP address to 0
              = 11001101000011110010010100100000
              = 205.15.37.32

Last Address: Set last 4 bits of IP address to 1
              = 11001101000011110010010100101111
              = 205.15.37.47 
Implementation: The following code uses the concepts mentioned above:
C++
Java
#include <iostream>#include <string.h>#include <stack>#include <vector>#include <math.h> using namespace std;    // Converts IP address to the binary formvector<int> bina(vector<string> str)    {    vector<int> re(32,0);        int a, b, c, d, i, rem;        a = b = c = d = 1;        stack<int> st;         // Separate each number of the IP address             a = stoi(str[0]);            b = stoi(str[1]);            c = stoi(str[2]);            d = stoi(str[3]);         // convert first number to binary        for (i = 0; i <= 7; i++)        {            rem = a % 2;            st.push(rem);            a = a / 2;        }         // Obtain First octet        for (i = 0; i <= 7; i++) {            re[i] = st.top();            st.pop();        }         // convert second number to binary        for (i = 8; i <= 15; i++) {            rem = b % 2;            st.push(rem);            b = b / 2;        }         // Obtain Second octet        for (i = 8; i <= 15; i++) {            re[i] = st.top();            st.pop();        }         // convert Third number to binary        for (i = 16; i <= 23; i++) {            rem = c % 2;            st.push(rem);            c = c / 2;        }         // Obtain Third octet        for (i = 16; i <= 23; i++) {            re[i] = st.top();            st.pop();        }         // convert fourth number to binary        for (i = 24; i <= 31; i++) {            rem = d % 2;            st.push(rem);            d = d / 2;        }         // Obtain Fourth octet        for (i = 24; i <= 31; i++) {            re[i] = st.top();            st.pop();        }         return (re);    }     // cls returns class of given IP addresschar cls(vector<string> str)    {        int a = stoi(str[0]);        if (a >= 0 && a <= 127)            return ('A');        else if (a >= 128 && a <= 191)            return ('B');        else if (a >= 192 && a <= 223)            return ('C');        else if (a >= 224 && a <= 239)            return ('D');        else            return ('E');    }     // Converts IP address    // from binary to decimal formvector<int> deci(vector<int> bi)    {         vector<int> arr(4,0);        int a, b, c, d, i, j;        a = b = c = d = 0;        j = 7;         for (i = 0; i < 8; i++) {             a = a + (int)(pow(2, j)) * bi[i];            j--;        }         j = 7;        for (i = 8; i < 16; i++) {             b = b + bi[i] * (int)(pow(2, j));            j--;        }         j = 7;        for (i = 16; i < 24; i++) {             c = c + bi[i] * (int)(pow(2, j));            j--;        }         j = 7;        for (i = 24; i < 32; i++) {             d = d + bi[i] * (int)(pow(2, j));            j--;        }         arr[0] = a;        arr[1] = b;        arr[2] = c;        arr[3] = d;        return arr;    } int main()    {          string ipr = "192.168.1.1/24";         // You can take user input here        // instead of using default address        // Ask user to enter IP address of form(x.y.z.t/n)        cout<<"IP address CIDR format is:"<< ipr;         // Separate IP address and n        string str1 = "";        int idx = 0;        int len = ipr.size();        len -= 3;        while(len--){            str1 += ipr[idx];            idx++;        }        cout<<endl;        cout<<"IP Address : " <<str1<<endl;         string str2 = "";        idx++;        str2 += ipr[idx];        idx++;        str2 += ipr[idx];        cout<<"Value of n : "<< str2<<endl;        // IP address        string tr = str1;         // Split IP address into 4 subparts x, y, z, t        //str = tr.split("\\.");        vector<string> str;         string temp;        int n = tr.size();        for(int i = 0; i < n; i++){            if(tr[i] >= 48 && tr[i] <= 57)                temp +=tr[i];            else{                str.push_back(temp);                temp = "";            }        }        str.push_back(temp);        //cout<<str[0]<<endl<<str[1]<<endl<<str[2]<<endl<<str[3]<<endl;         vector<int> b;         cout<<endl;         // Convert IP address to binary form        b = bina(str);         n = stoi(str2);        vector<int> ntwk(32,0);        vector<int> brd(32,0);        int t = 32 - n;         // Obtaining network address        for (int i = 0; i <= (31 - t); i++) {             ntwk[i] = b[i];            brd[i] = b[i];        }         // Set 32-n bits to 0        for (int i = 31; i > (31 - t); i--) {             ntwk[i] = 0;        }         // Obtaining Broadcast address        // by setting 32-n bits to 1        for (int i = 31; i > (31 - t); i--) {             brd[i] = 1;        }         cout<<endl;         // Obtaining class of Address        char c = cls(str);        cout<<"Class : " << c << endl;         // Converting network address to decimal        vector<int> nt = deci(ntwk);         // Converting broadcast address to decimal        vector<int> br = deci(brd);         // Printing in dotted decimal format        cout<<"First Address : " << nt[0] << "." <<nt[1] <<"." << nt[2] <<"." << nt[3]<<endl;         // Printing in dotted decimal format        cout<<"Last Address : "  <<br[0] << "." <<br[1] << "." << br[2] <<"." << br[3] << endl;         //Printing Number of Addresses in Block        cout<<"Total Number of Addresses :" <<br[3]-nt[3]+1<<endl;         return 0;}
import java.util.*;import java.io.*;import java.net.*;import java.lang.Math; class Ip {         // Converts IP address to the binary form    public static int[] bina(String[] str)    {        int re[] = new int[32];        int a, b, c, d, i, rem;        a = b = c = d = 1;        Stack<Integer> st = new Stack<Integer>();                 // Separate each number of the IP address        if (str != null)        {            a = Integer.parseInt(str[0]);            b = Integer.parseInt(str[1]);            c = Integer.parseInt(str[2]);            d = Integer.parseInt(str[3]);        }                 // convert first number to binary        for (i = 0; i <= 7; i++)        {            rem = a % 2;            st.push(rem);            a = a / 2;        }                 // Obtain First octet        for (i = 0; i <= 7; i++) {            re[i] = st.pop();        }                 // convert second number to binary        for (i = 8; i <= 15; i++) {            rem = b % 2;            st.push(rem);            b = b / 2;        }                 // Obtain Second octet        for (i = 8; i <= 15; i++) {            re[i] = st.pop();        }                 // convert Third number to binary        for (i = 16; i <= 23; i++) {            rem = c % 2;            st.push(rem);            c = c / 2;        }                 // Obtain Third octet        for (i = 16; i <= 23; i++) {            re[i] = st.pop();        }                 // convert fourth number to binary        for (i = 24; i <= 31; i++) {            rem = d % 2;            st.push(rem);            d = d / 2;        }                 // Obtain Fourth octet        for (i = 24; i <= 31; i++) {            re[i] = st.pop();        }                 return (re);    }         // cls returns class of given IP address    public static char cls(String[] str)    {        int a = Integer.parseInt(str[0]);        if (a >= 0 && a <= 127)            return ('A');        else if (a >= 128 && a <= 191)            return ('B');        else if (a >= 192 && a <= 223)            return ('C');        else if (a >= 224 && a <= 239)            return ('D');        else            return ('E');    }         // Converts IP address    // from binary to decimal form    public static int[] deci(int[] bi)    {                 int[] arr = new int[4];        int a, b, c, d, i, j;        a = b = c = d = 0;        j = 7;                 for (i = 0; i < 8; i++) {                         a = a + (int)(Math.pow(2, j)) * bi[i];            j--;        }                 j = 7;        for (i = 8; i < 16; i++) {                         b = b + bi[i] * (int)(Math.pow(2, j));            j--;        }                 j = 7;        for (i = 16; i < 24; i++) {                         c = c + bi[i] * (int)(Math.pow(2, j));            j--;        }                 j = 7;        for (i = 24; i < 32; i++) {                         d = d + bi[i] * (int)(Math.pow(2, j));            j--;        }                 arr[0] = a;        arr[1] = b;        arr[2] = c;        arr[3] = d;        return arr;    }         public static void main(String args[])    {         int i;        String[] str = new String[4];        String ipr = "192.168.1.1/24";         // You can take user input here        // instead of using default address        // Ask user to enter IP address of form(x.y.z.t/n)        System.out.println("IP address CIDR format is:" + ipr);                 // Separate IP address and n        String[] str1 = ipr.split("/");                 // IP address        String tr = str1[0];                 // Split IP address into 4 subparts x, y, z, t        str = tr.split("\\.");         int[] b = new int[32];         System.out.println();                 // Convert IP address to binary form        b = bina(str);         int n = Integer.parseInt(str1[1]);        int[] ntwk = new int[32];        int[] brd = new int[32];        int t = 32 - n;                 // Obtaining network address        for (i = 0; i <= (31 - t); i++) {                         ntwk[i] = b[i];            brd[i] = b[i];        }                 // Set 32-n bits to 0        for (i = 31; i > (31 - t); i--) {                         ntwk[i] = 0;        }                 // Obtaining Broadcast address        // by setting 32-n bits to 1        for (i = 31; i > (31 - t); i--) {                         brd[i] = 1;        }                 System.out.println();         // Obtaining class of Address        char c = cls(str);        System.out.println("Class : " + c);                 // Converting network address to decimal        int[] nt = deci(ntwk);                 // Converting broadcast address to decimal        int[] br = deci(brd);         // Printing in dotted decimal format        System.out.println("Network Address : " + nt[0]                     + "." + nt[1] + "." + nt[2] + "." + nt[3]);                 // Printing in dotted decimal format        System.out.println("Broadcast Address : "                     + br[0] + "." + br[1] + "." + br[2] + "." + br[3]);    }}
Output: 
IP address CIDR format is:192.168.1.1/24


Class : C
Network Address : 192.168.1.0
Broadcast Address : 192.168.1.255 
 
kaustubhdwivedi1729
vaibhavsinghtanwar3
avtarkumar719
Computer Networks-IP Addressing
Computer Networks
Computer Networks
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