Code:sequential Update() // I: input, C: correct, D: delete getNextTrans(); getNextMaster(); while (masterKey ≠ EOF and transKey ≠ EOF) do { if(masterKey < transKey) then { output master record to new master; getNextMaster(); } else { // if masterKey >= transKey if ( masterKey = transKey) then { case { code = 'I': print "error: duplicate record key"; getNextTrans(); code = 'C': make change in master record; output master record to new master; getNextTrans(); getNextMaster(); code = 'D': getNextMaster(); getNextTrans(); else: print 'error: invalid update code'; getNextTrans(); } // end case } else { // if masterKey > transKey noMatch(); } } end // sequentialUpdate() getNextTrans() if (trans is end of file) then transKey <- EOF else input transaction record; end //getNextTrans() getNextMaster() if (master is end of file) then masterKey <- EOF else input master record; end //getNextMaster() noMatch() //if masterKey > transKey case { code = 'I': build new record from trans record; output new record to new master; getNextTrans(); code = 'C': print 'error: no matching master record for trans key; getNextTrans(); code = 'D': print 'error: invalid update code'; getNextTrans(); else: print 'error: invalid update code'; getNextTrans(); } } //end case end //noMatch can anyone describe it to me pls.