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Subnetting.java
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Subnetting.java
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import java.util.Scanner;
public class Subnetting {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter IP Address: ");
String ip = sc.next();
String ipad[] = ip.split("\\.");
int cc = Integer.parseInt(ipad[0]);
String mask = "";
if (cc > 0 && cc <= 127) {
mask = "255.0.0.0";
System.out.println("Class A IP Address");
} else if (cc >= 128 && cc <= 191) {
System.out.println("Class B IP Address");
mask = "255.255.0.0";
} else if (cc >= 192 && cc <= 223) {
System.out.println("Class C IP Address");
mask = "255.255.255.0";
} else if (cc >= 224 && cc <= 239) {
System.out.println("Class D IP Address, used for Multcast");
mask = "255.0.0.0";
} else if (cc >= 240 && cc <= 254) {
System.out.println("Class E IP Address used for Experimental Use");
mask = "255.0.0.0";
} else {
System.out.println("Invalid IP Address");
System.exit(0);
}
System.out.println("Subnet Mask: ");
System.out.println(mask);
String networkaddr = "";
String lastaddr = "";
String[] ipaddr = ip.split("\\.");
String msk[] = mask.split("\\.");
for (int i = 0; i < 4; i++) {
int x = Integer.parseInt(ipaddr[i]);
int y = Integer.parseInt(msk[i]);
int z = x & y;
networkaddr += z + ".";
int w = z | (y ^ 255);
lastaddr += w + ".";
}
System.out.println("First IP of the block:\n " + networkaddr);
System.out.println("Last IP of the block, i.e. BroadCast Address:\n " + lastaddr);
sc.close();
}
}
/* ALGORITHM
* 1. Start
* 2. Accept IP address
* 3. Based on the first part of the IP address classify it into
* it's class.
* 4. According to its class assign it's subnet mask.
* 5. Now convert the IP address and Subnet mask into binary form
* 6. Perform bitwise AND of all the bits.
* 7. Convert the obtained binary number into its decimal equivalent.
* 8. The obtained decimal number is the first IP of the block.
* 9. Stop
*/