PDU.java

import static java.lang.System.out;

public class PDU {
    public static void main(String [] args) {
        String smsc = args[0];
        String smsc_format = "92";
        if(smsc.substring(0,1).equals("+")) {
            smsc_format = "91";
            smsc = smsc.substring(1);
        }
        else if(!smsc.substring(0,1).equals("0")) {
            smsc_format="91";
        }
        
        else {}

        if (smsc.length() %2 != 0) {
            smsc += 'F';
        }
        String smsc_number = convert(smsc);
        smsc = smsc_format + smsc_number;
        int smsc_length = smsc.length() / 2;
        if (smsc_length < 10) {
            smsc = "0" + smsc_length + smsc;
        } else {
            smsc = smsc_length + smsc;
        }

        out.println("smsc_format = " + smsc_format);
        out.println("smsc = " + smsc);

    }
    private static String convert(String input) {
        char[] output = new char[input.length()];
        for (int i = 0; i < input.length(); ++i ){
            if ( i % 2 == 0 ) {
                output[i] = input.charAt(i+1);
            } else {
                output[i] = input.charAt(i-1);
            }
        }
        return new String(output);
    }


}