Automatic machine grading programs

In connection with introductory programming and numerical analysis courses at Stanford University, grading programs have been used intermittently since 1961. The original idea came from the TEACH routine devised at Carnegie Tech. by A. J. Perlis and others. Our programs furnish data, check student answers in various ways, keep track of running time, and keep a -and-ldquo;grade book-and-rdquo; for the problems. They do not check the quality of the programming in any other way. In contrast to the TEACH routine, the Stanford routines, called GRADER1, GRADER2, etc., are written separately for each problem. The most flexible and useful system was used with the Burroughs 220 computer in the BALGOL language, a dialect of ALGOL 58, and will now be described. Each grader program was written as a BALGOL-language procedure. It was then compiled together with a procedure called BUTTERFLY, written by Roger Moore of Stanford. The result was a relocatable machine-language procedure, with a mechanism for equating its variables to variables of any BALGOL program, in just the form of the BALGOL compiler's own machine-language library procedures (SIN, WRITE, READ, etc.). Finally, the grader program was added to the compiler library tape for the duration of its use.