This paper describes a system which provide s a visual demonstration of the structure and flo w of an ALGOL program . The program is displayed o n a CRT and executed interpretively, highlightin g each statement prior to execution and showing th e result of the statement after execution . Th e primary use of the system is to demonstrat e program operation in a classroom environment . I t has also been used as an automatic benchcheckin g aid .Introductio n

This paper describes a system which provide s a visual demonstration of the structure and flo w of an ALGOL program . The program is displayed o n a CRT and executed interpretively, highlightin g each statement prior to execution and showing th e result of the statement after execution . Th e primary use of the system is to demonstrat e program operation in a classroom environment . I t has also been used as an automatic benchcheckin g aid .Introductio n