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Java for-loop generating MAC addresses

Trying to make a loop of MAC address values with:

String macAddr = "AA:BB:CC:DD:";
char[] chars = {'A', 'B', 'C', 'D', 'E', 'F'};
String[] strings = {"0", "0", "0", "0"};

for (int i=0; i<strings.length; i++)
{
    //counter from 0 to F
    for (int d = 0; d <= 9; d++)
    {
        strings[i] = ""+d;
        print();
    }
    for (int d = 0; d< chars.length; d++)
    {
        strings[i] = ""+chars[d];
        print();
    }
}

where print() is:

System.out.println(macAddr+strings[3]+strings[2]+":"+strings[1]+strings[0]);

But i'm getting run-over:

AA:BB:CC:DD:00:0D
AA:BB:CC:DD:00:0E
AA:BB:CC:DD:00:0F
AA:BB:CC:DD:00:0F
AA:BB:CC:DD:00:1F
AA:BB:CC:DD:00:2F
AA:BB:CC:DD:00:3F

The two problems are the dual values at each crossover (e.g. AA:BB:CC:DD:00:0F) and the values stopping at F on each value.

I'm trying to get them as:

AA:BB:CC:DD:00:0D
AA:BB:CC:DD:00:0E
AA:BB:CC:DD:00:0F
AA:BB:CC:DD:00:11
AA:BB:CC:DD:00:12
AA:BB:CC:DD:00:13

etc.

Cheers :)

like image 537
spuriosity Avatar asked Dec 16 '22 09:12

spuriosity


1 Answers

Use a long to store your mac address and create a small function to convert it to a String.

public static String toMacString(long mac) {

    if (mac > 0xFFFFFFFFFFFFL || mac < 0)
        throw new IllegalArgumentException("mac out of range");

    StringBuffer m = new StringBuffer(Long.toString(mac, 16));
    while (m.length() < 12) m.insert(0, "0");

    for (int j = m.length() - 2; j >= 2; j-=2)
        m.insert(j, ":");
    return m.toString().toUpperCase();
}

public static void main(String[] args) {

    long mac = 0xAABBCCDD0000L;

    for (long i = 0; i < 1000; i++)
        System.out.println(toMacString(mac++));
}

Example output:

AA:BB:CC:DD:00:00
AA:BB:CC:DD:00:01
AA:BB:CC:DD:00:02
AA:BB:CC:DD:00:03
AA:BB:CC:DD:00:04
AA:BB:CC:DD:00:05
AA:BB:CC:DD:00:06
....
AA:BB:CC:DD:03:DF
AA:BB:CC:DD:03:E0
AA:BB:CC:DD:03:E1
AA:BB:CC:DD:03:E2
AA:BB:CC:DD:03:E3
AA:BB:CC:DD:03:E4
AA:BB:CC:DD:03:E5
AA:BB:CC:DD:03:E6
AA:BB:CC:DD:03:E7
like image 199
dacwe Avatar answered Dec 27 '22 10:12

dacwe