ERROR Example
10 CLEAR SCREEN
20 ON ERROR CALL Testerr
30 Forceerr
40 PRINT "You should never see this line."
50 END
60 SUB Forceerr
70 !force error
80 PRINT SYSTEM$("NON EXISTAT ") !gives error 401
90 SUBEND
100 SUB Testerr
110 BEEP
120 PRINT "Error *";ERRN;"on line";ERRLN
130 STOP
140 SUBEND
