NELIAC—dialect of ALGOL

IIntr°ducti°n There is a technical distinction between (a) and (b). } In the past the description of a large scale computa-In the case of the "do" statement in (a), after completion tional problem was given in the form of a "flow diagram," of the process specified by statement S1, the flow is to i designed to express to the individual in the simplest way I the complexities of the problem, but not at suitable as 1~, ~ direct; input to the computing machine. [[he first step It0 help the "coder" was to prepare systems which would r ~cccpt algebraic formulas in their natural form and gen-lerate a sequence of commands for some particular com-i puter which when executed would produce the required ]result. This more or less provided for the working boxes of ~ow diagrams, ttowever, it automated that part of the problem which was in many cases easiest for the human t0 do. Not only was this the easiest but, perhaps as a consequence, this part of the problem was less subject to roman error. The system described in this paper is an ~tIempt to alleviate some of the dittieulties of the rest of the problem. The items to be processed in an automatic computing lnaehine must be assigned memory locations. The various instructions to the computer which eause it to perform the proper sequence of events must also be stored in the memory of the computing machine. This assignment of storage, as already noted, is simply a bookkeeping task which can be performed by the computer. Consider now the interconnecting lines of the flow diagram. The first; requirement is a "language" which can simply and clearly express the same ideas expressed by the flow diagram. The specification of the various events to be accomplished by the computer will be referred to as "statements." The statements inside the regions of the fl0w diagram are usually arithmetic or logical in character or have to do with input/output processes. The interconnecting lines on the flow diagram correspond to "directive" statements. These may be simple in character , indicating which region of statements is to be done alter a particular region is finished. Some regions may h~ve two exits and be conditional in character, the particular exit to be used depending, for example, upon the relative magnitudes of two variables. Such conditional situations can be expressed by so-called "decision" statements. If S1, …