| 词条 | Short Code (computer language) |
| 释义 |
| name = Short Code | paradigm = | released = {{Start date|1950}} | developer = William F Schmidt, A.B. Tonik, J.R. Logan | influenced by = ENIAC Short Code | influenced = Intermediate programming language, OMNIBAC Symbolic Assembler }}Short Code was one of the first higher-level languages ever developed for an electronic computer.[1] Unlike machine code, Short Code statements represented mathematic expressions rather than a machine instruction. Also known as an automatic programming, the source code was not compiled but executed through an interpreter to simplify the programming process; the execution time was much slower though.[2] HistoryShort Code was proposed by John Mauchly in 1949 and originally known as Brief Code. William Schmitt implemented a version of Brief Code in 1949 for the BINAC computer, though it was never debugged and tested. The following year Schmitt implemented a new version of Brief Code for the UNIVAC I where it was now known as Short Code (also Short Order Code). A revised version of Short Code was developed in 1952 for the Univac II by A. B. Tonik and J. R Logan.[3] While Short Code represented expressions, the representation itself was not direct and required a process of manual conversion. Elements of an expression were represented by two-character codes and then divided into 6-code groups in order to conform to the 12 byte words used by BINAC and Univac computers.[4] For example, the expression: was converted to Short Code by a sequence of substitutions and a final regrouping: X3 = ( X1 + Y1 ) / X1 * Y1 substitute variables X3 03 09 X1 07 Y1 02 04 X1 Y1 substitute operators and parentheses. Note multiplication is represented by juxtaposition. 07Y10204X1Y1 group into 12-byte words. 0000X30309X1 Along with basic arithmetic, Short Code allowed for branching and calls to a library of functions. The language was interpreted and ran about 50 times slower than machine code.[5] See also
References1. ^Sebesta, W.S Concepts of Programming languages. 2006;M6 14:18 pp.44. {{ISBN|0-321-33025-0}} 2. ^Sebesta, W.S Concepts of Programming languages. 11E; Chapter 2, pp.39. {{ISBN|978-0133943023}} 3. ^Schmitt, William F. The UNIVAC SHORT CODE. Annals of the History of Computing (1988) 10:pages 7-8 4. ^Schmitt, William F. The UNIVAC SHORT CODE. Annals of the History of Computing (1988) 10:page 15 5. ^Malik, Masud Ahmad. Evolution of the High Level Programming Languages: A Critical Perspective. ACM SIGPLAN Notices (December 1998) 33(12) page 74.
External links 2 : Procedural programming languages|Programming languages created in 1950 |
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