Unlike most subsequent BASICs, Dartmouth BASIC, from the Third Edition onwards, had a matrix keyword, codice_2, which could prefix a number of other commands to operate on entire arrays of data with a single command. In this example, from the 1968 manual, codice_157 is used to input a series of variables. When the user enters nothing on a line, this process ends and the total number of elements is accessed in the codice_158 pseudovariable. The code then adds up all of the individual elements in the matrix and calculates the average. The Third Edition also added indentation, which is used here to clarify the loop structure.