How to find the mandatory fields in the table manually

USING SYSDICTTABLE CLASS

static void mandatoryFieldsOfATable(Args _args)
{
    SysDictTable sysDictTable;
    SysDictField sysDictField;
    TableId tableId;
    Counter counter;
    ;
    sysDictTable = new SysDictTable(tablenum(CustTable));
    for(counter = 1;counter <= sysDictTable.fieldCnt(); counter++)
   {
        sysDictField = new sysDictField(sysDictTable.id(), sysDictTable.fieldCnt2Id(counter));

       if(sysDictField.mandatory())
                 info(sysDictField.name());
    }
}

The output of the above code will be