PYTHON FUNDAMENTALS OF COMP.pptx
- 31. Plankalkül (1941) • Plankalkül is a computer language developed for engineering purposes by Konrad Zuse, a German Civil Engineer and inventor. • It was invented as the programming language for the Z3, the first programmable electromechanical computing machine, which Zuse built on his own in 1941. Konrad Zuse • It was the first high-level non-von Neumann programming language to be designed for a computer and was designed between 1943 and 1945. • It was not known for a long time owing to a combination of factors such as conditions in wartime and postwar Nazi Germany.
- 32. Short Code (1949) • Short Code was the first higher-level language ever developed and used for a computer. • Short Code was designed in 1949 by John Mauchly, co-inventor of UNIVAC I, the first commercial computer produced in the United States. John Mauchly UNIVAC
- 33. Short Code (1949) • Unlike machine code, Short Code statements represented mathematical expressions rather than a machine instruction. • While Short Code represented expressions, the representation itself was not direct and required a conversion process then called automatic programming. • 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.
- 34. A-0 (1951) • The A-0 system, written by Grace Hopper in 1951 and 1952 for the UNIVAC I, was the first compiler system ever developed for a computer. Grace Hopper and UNIVAC Grace Hopper
- 35. A-0 (1951) • A-0 functioned more as a loader/linker than the modern notion of a compiler. • A program was specified as a sequence of subroutines and arguments. The subroutines were identified by a numeric code and the arguments to the subroutines were written directly after each subroutine code. • The A-0 system converted the specification into machine code that could be fed into the computer in a second pass to execute the program.
- 36. A-0 (1951) • A similar systems was invented independently by David Wheeler and Maurice Wilkes for the EDSAC computer in 1951. Maurice Wilkes and EDSAC
- 38. FORTRAN
- 39. Fortran • IBM Mathematical Formula Translating System, later popularly know as Fortran. • Originally developed by a team lead by John Backus at IBM in the 1950s for scientific and engineering applications on the IBM704, introduced in 1954. • General-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing. John Backus • Originally designed to improve on the economics of programming, as programming using low level languages had become to be more costly than the time it actually saved.
- 40. Fortran • The solution was to design a higher level programming language enabling scientists to write programs using a mathematical notation/language. • Great emphasis was put on the efficiency of the translated machine code, which is still the case today, explaining why Fortran programs are still considered as a benchmark for execution speed. • Emphasis was put on number computations. Only much later was it possible to have Fortran programs manipulate characters or strings.
- 41. Fortran • Features introduced by earlier versions of Fortran: • Comments • Assignment statement using complex expressions • Control structures (conditional, loop) • Subroutines and functions used similarly to the mathematical notion of function • Formatting of input/output • Machine independent code • Procedural programming • Arrays • Early development of compilers • Showed the importance/possibility/relevance of higher-level programming languages • Compiler development tools/techniques • Optimizing compiler
- 42. Fortran • Reasons explaining Fortran’s early success: – Made efficient use of programmer’s time – Easy to learn and use by scientists – Was fully supported by IBM for many years – At the time, most applications and users were scientific – Simplified many tedious tasks such as input/output formatting – Compiler was generating very well optimized code • Fortran is still one of the most popular languages in the area of high- performance computing and is the language used for programs that benchmark and rank the world's fastest supercomputers.
- 43. COBOL
- 44. Cobol • A specification of COBOL was initially created during the second half of 1959 by Grace Hopper. • The specifications were to a great extent inspired by the Grace Hopper’s FLOW- MATIC and IBM’s COMTRAN languages. Left to right: Ron Hamm, John L. Jones, Dr. Jan Prokop, Oliver Smoot, Tom Rice, Donald Nelson, Commodore Grace M. Hopper, Michael O'Connell and Howard Bromberg. © Computer History Museum • Acronym for COmmon Business-Oriented Language • Primary domain in business, finance, and administrative systems.
- 45. Cobol • Initial meeting for the creation of COBOL (then named CBL) was held at the Pentagon in May 1959. • The meeting agreed to the following requirements: – Use of English (as business is in English) – Ease of use (even at expense of performance) – Both these requirements aimed at its use by business people • Emphasis was put on immediate action, as many other such languages/systems were attempted at the time. • By December 1959, a first version was defined, which was refined in 1961 and 1962. • A standard version was defined in 1968. Further standardized evolutions were defined in 1974, 1985 and 2002.
- 46. Cobol • First programming language advocated by the United States Department of Defense, which contributed to its success. • The development of Cobol paralleled that of Fortran. • It is a data processing language, making it different from Fortran and Algol. • Puts explicit emphasis on the description of the manipulated data at two levels: • Machine-dependent description (environment division) providing a connection between the Cobol program and the data files as stored on a specific media. • Machine-independent logical description of data as manipulated by procedures.
- 47. Cobol • Positive: • Macros • Hierarchical data structures • Descriptive variable names • Elaborated Input/Output formatting • Built-in searching/sorting procedures • Backed-up by Department of Defense • Negative: • Poor performance of early compilers • Restricted to business data applications
- 48. ALGOL
- 49. Algol • ALGOL (ALGOrithmic Language) is a family of imperative computer programming languages originally developed in the mid 1950s that greatly influenced many other programming languages. Some of the original designers or Algol. Top row: John McCarthy, Fritz Bauer, Joe Wegstein. Bottom row: John Backus, Peter Naur, Alan Perlis. • Introduced by a joint committee of American (ACM) and European (GAMM) experts . • GAMM: Gesellschaft für Angewandte Mathematik und Mechanik ("Society of Applied Mathematics and Mechanics") • ACM: Association for Computing Machinery
- 50. Algol • According to John Backus, the original goals of the original meeting in ETH Zurich were: – To provide a means of communicating numerical methods and other procedures between people – To provide a means of realizing a stated process on a variety of machines. • Original objectives of Algol: – Machine independence – As close as possible to mathematical notation – Usable for the description of algorithms in publications – Easily translatable to machine instructions – Avoid some of the perceived problems with FORTRAN – Language simplicity
- 51. PL/I
- 52. PL/I • With Fortran and Cobol, there were two distinct “kinds” of programmers. Fortran emphasized floating point arithmetic, arrays, procedures, fast computation. Cobol emphasized decimal arithmetic, fast asynchronous input/output, string handling, efficient search/sort routines. • More and more, there came a need for all these features to be incorporated in a single language. IBM 360 • When IBM designed the famous IBM360 computer, it saw the opportunity to design a new general- purpose language designed specifically for it. • This language was named PL/I (Programming Language 1). It was originally developed in 1964-1966.
- 53. PL/I • Goals of PL/I: – Provide features of Fortran, augmented with the capacities of Cobol. – Clarity of language. – Incorporating current programming languages innovations. – Performance of compiled code competitive with that of Fortran. – Extensibility to new hardware and other application areas. – Improve programming productivity - transferring effort from programmer to compiler. – Machine and operating system independence.
- 54. PL/I • This created a language with very numerous features and requirements, including many innovative ones: – Reference data types – User-defined data types – Concurrency – Dynamic arrays – Auto-correcting compiler – String handling – Machine independence – Efficiency – Exception handling – I/O control system – Report-generation – Recursion
- 55. PASCAL
- 56. Pascal • Pascal is a very influential imperative and procedural programming language, designed in 1968-1969 and published in 1970 by Niklaus Wirth. • Small and efficient language intended to encourage good programming practices using structured programming and data structuring. Nicklaus Wirth • Pascal is based on the ALGOL-60 programming language and named in honor of the French mathematician and philosopher Blaise Pascal.
- 57. Pascal • Pascal, in its original form, is a purely procedural language and includes the traditional array of ALGOL-60 control structures. • Pascal also has many data structuring facilities and other abstractions which were not included in the original ALGOL 60, such as: – user-defined type definitions – records – case statement – pointers – enumerations – sets • Such constructs were inspired from Simula 67, ALGOL 68, and Wirth and Hoare’s ALGOL W.
- 58. SIMULA
- 59. Simula • Simula 67 introduced objects, classes, subclasses, virtual methods, coroutines, discrete event simulation, and featured garbage collection. • Simula is considered the first object-oriented programming language. Ole-Johan Dahl and Kristen Nygaard • Simula was developed in the 1960s at the Norwegian Computing Center in Oslo, by Ole-Johan Dahl and Kristen Nygaard. • Syntactically, it is a superset of Algol 60.
- 60. Simula • As its name implies, Simula was designed for doing simulation. • Simulation systems are modelled by a series of state changes that occur in parallel through the interaction of the elements of the system as they compete for restricted system resources. • Each type of element of the system is composed of its internal state, as well as a set of procedures that define its own behaviour. • Elements interact with one another as a system by calling some of the other elements’ procedures. • This is the baseline of what we now call object-oriented programming.
- 61. Simula • Simula was based on Algol 60 with the addition of the concept of class. • Simula allowed to declare classes of objects, create instances of these classes, name the instances, and even form a hierarchical structure of class declarations. • Simula was designed solely as a language to be used for simulations. However, in retrospect, its concept can clearly be used as a general- purpose language. • The impact of Simula on subsequent languages is great but little recognized, as most people think that object-oriented programming is a relatively new concept.
- 62. C
- 63. C • C is a general-purpose programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. • Although C was designed for implementing system software, it is also widely used for developing portable application software. Dennis Ritchie • C has become one of the most popular programming languages. It is widely used on many different software platforms, and there are few computer architectures for which a C compiler does not exist. C has greatly influenced many other programming languages, most notably C++, which originally began as an extension to C.
- 64. C • C was influenced by the languages BCPL and B (systems languages), who were influenced by Algol and Fortran. • C was originally designed in 1969-1972 with the following goals in mind: • to be compiled using a relatively straightforward compiler • to provide low-level access to memory • to provide language constructs that map efficiently to machine instructions • to require minimal run-time support • In 1977-1979, portability emerged when portability of the Unix operating system was being demonstrated. • In 1978, the famous book The C Programming Language was published, written by Brian Kernigan and Dennis Ritchie.
- 65. C++
- 66. C++ • C++ is a statically typed, multi-paradigm, compiled, general-purpose programming language. • It is a middle-level language, as it comprises a combination of both high-level and low-level language features. • It was developed by Bjarne Stroustrup starting in 1979 at Bell Laboratories as an enhancement to the C programming language following the object- oriented principles pioneered by Simula. • Goals: • Augment C with the notion of classes and inheritance • Keep the same performance as C • Keep same applicability as C Bjarne Strousroup
- 67. C++ • Bjarne Stroustrup describes some rules that he used for the design of C++: – Statically typed, general-purpose language, as efficient and portable as C – Direct and comprehensive support for multiple programming styles (procedural programming, data abstraction, object-oriented programming, and generic programming) – Give the programmer choice, even if this makes it possible for the programmer to choose incorrectly – As compatible with C as possible, providing a smooth transition from C – Avoid features that are platform specific or not general purpose – Not incur overhead for features that are not used – Function without a sophisticated programming environment
- 68. JAVA
- 69. Java • Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. James Gosling • Java is a general-purpose, concurrent, class-based, and object- oriented, and is specifically designed to have as few implementation dependencies as possible. • It is intended to let application developers "write once, run anywhere“, meaning that once it has been compiled, it can be executed on any platform.
- 70. Java • It was originally designed as a language to be used for embedded electronic devices, with the following goals: – Simplicity – Reliability – Object-orientation • The main languages available for that purpose were C and C++. • It was found that these were not suitable given the stated requirements. • Java was thus defined as a simpler and safer version of C++.
- 71. Java • Java thus derives much of its syntax from C++ but has a simpler object model and fewer low-level facilities: – No free functions – No multiple inheritance – No pointers – No explicit memory management – Array boundary checking – No structs and unions • Some additions enhance Java’s scope of application: – Extreme portability – Concurrency using threads – Graphical user interface libraries – Database adapters – Networking, distributed computing