Lecture 02: Overview and Evaluation of Programming Languages

What does Fortanm stand for?

FORmula TRANslation

What was the first well known highlevel programming language?

Fortran

Who lead the fortrand dev team

John Backus at IBM

What were the dev goals

[1] lower the costs involved with programming and debugging; [2] compete with “hand-coded” (assembly language) programs in terms of execution speed.

When was the first fortan compiler compleated

1957

What wear the features of early fortran

assignments, DO loops, three-way arithmetic IF statements, GOTO statements; integers, reals, arrays (and very basic string handling)

early for tran source code has a ___ source code format

Early Fortran source code has strict source code format,

Early programs were entered on a _____ keyboard onto ___ column punched cards

Early programs were entered on a keypunch keyboard onto 80 column punched cards

What is the TPK algorithm

[1] A program introduced by Donald Knuth and Luis Trabb Pardo to illustrate the evolution of computer programming languages. [2] a small program that involved arrays, indexing, mathematical functions, subroutines, I/O, conditionals and iteration.

Reflecting punched card input practice, Fortran programs were originally written in a _____ column format.

Reflecting punched card input practice, Fortran programs were originally written in a fixed column format.

A letter "__" in column __ caused the entire card to be treated as a comment and ignored by the compiler.

A letter "C" in column 1 caused the entire card to be treated as a comment and ignored by the compiler.

the card was divided into ___ fields

the card was divided into four fields

Columns 1 to 5 were the label field: a sequence of digits here was taken as a label for the purpose of a ___ or a ____ reference in a ____ or ___ statement.

Columns 1 to 5 were the label field: a sequence of digits here was taken as a label for the purpose of a GOTO or a FORMAT reference in a WRITE or READ statement.

Column __ was a continuation field: a non-blank character here caused the card to be taken as a continuation of the statement on the previous card.

Column 6 was a continuation field: a non-blank character here caused the card to be taken as a continuation of the statement on the previous card.

Columns 7 to __ served as the statement field.

Columns 7 to 72 served as the statement field.

Columns __ to 80 were ignored, so they could be used for identification information (e.g., a sequence number which could be used to re-order cards if a stack of cards was dropped)

Columns 73 to 80 were ignored, so they could be used for identification information (e.g., a sequence number which could be used to re-order cards if a stack of cards was dropped)

These restrictions are removed in Fortran __, which is a free-form language

These restrictions are removed in Fortran 90, which is a free-form language

Most variables are declared _____ (variables with names with first letters between I and N are INTEGERs, others are reals).

Most variables are declared implicitly (variables with names with first letters between I and N are INTEGERs, others are reals).

COBOL (COmmon Business Oriented Language) was created at the end of the _____ by a committee of the US Dept of Defense

COBOL (COmmon Business Oriented Language) was created at the end of the 1950s by a committee of the US Dept of Defense

It was designed for ___ ___ _____ rather than for scientific computing.

It was designed for business data processing rather than for scientific computing.

Its ______ syntax had the intention that managers as well as programmers should be able to ___the code; e.g.: SUBTRACT TAX FROM GROSS-PAY GIVING NET-PAY.

Its verbose syntax had the intention that managers as well as programmers should be able to read the code; e.g.: SUBTRACT TAX FROM GROSS-PAY GIVING NET-PAY.

COBOL has had many _____ e.g., programmers who feel that its verbosity simply increases program length, not ______

COBOL has had many critics, e.g., programmers who feel that its verbosity simply increases program length, not readability

Like Fortran, COBOL has seen _____ use since first introduced, initially pushed by the __ ___.

Like Fortran, COBOL has seen continued use since first introduced, initially pushed by the US DoD.

A large amount of ___ in business ____ running today has been written in COBOL.

A large amount of code in business applications running today has been written in COBOL.

what are the mahor concepts of Algo 60?

[1] use of formal notation for syntax (BNF notation - lecture 5) [2] block structure (with locally-defined variables) [3] recursive procedures [4]“readable” if and for statements.

It is a direct descendant of ____

It is a direct descendant of Algol

Pascal was intened to be more ___ to compete with ____ as a ____purpose lang

Pascal was intened to be more effiecet to compete with fortran as a general purpose lang

Pascal became popular in the late 70s as a ____ language in universities

Pascal became popular in the late 70s as a teaching language in universities

What is required as the first line of a pascl program?

The program statement is a required first line of every program.

every pascal program must have a name, t/f?

True

whast does "input" mean in a pascal program?

input means that the keyboard may be used to put information into the program.

What does "output mean in a pascal program?

output means that the program may write information to the video display.

what key word does every pascal program have at the start

begin

what key word does every pascal program have at the finish

end

What are the features of a scripting language?

Typically scripting languages are typeless, with relatively simple syntax and semantics, interpreted and intended to be very fast to learn and write in

What re the features of the logical programming language prolog?

-Variables-Constants-Structures[1] Vars begin with a capital letter[2] Constants are either atoms, like english or integers, eg 6[3] Structures consist of a functor and arguments, eg speaks(Y, english). Speaks is the functor. Y, english are arguments.

A Prolog program consists of a collection of __ and __

A Prolog program consists of a collection of facts and rules. Prolog program containing 2 facts and one rule. speaks(mary, russian). speaks(jake, english). talkswith(X, Y):- speaks(X, L), speaks(Y, L), X \= Y

Prolog programs are used to answer ____ (although simple arithmetic operations are possible)

Prolog programs are used to answer queries (although simple arithmetic operations are possible)

describe a Prolog query

a fact or rule that initiates a search for success. It specifies a search goal by naming variables that are of interest. E.g.,?- speaks(Who, russian). asks for an instantiation of the variable Who for which the query speaks(Who, russian) succeeds.

what are the language evaluation criteria? S__, l__ e__, O__, C__ s__, D__ t__, E__, T__ c__, E__ h__

what are the language evaluation criteria? Simplicity, lexical elements, Orthogonality, Control structures, Data types, Expressiveness, Type checking, Expectation handling

what are the language evaluation criteria?

what are the language evaluation criteria? Simplicity, lexical elements, Orthogonality, Control structures, Data types, Expressiveness, Type checking, Expectation handling

explain Simplicity

[1] lang' with small num' of constructs is easier to learn[2] eg complex language, C has 4ways of incrementing an int var: i=i+1; i+=1; i++; ++i;[3] this may be bad for the readability of C programs, but may make them easier to write

explain Lexical Elements

[1] The form that the individual lexical elements (i.e. words, symbols) of a language take can affect language readability. [2] The meaning of a symbol or keyword should ideally be obvious from its name.

Explain Orthogonality

[1] a lang' has a small number of control n data constructs (eg: data types), that can be combined in a small number of ways and where every combination is legal and meaningful. [2] no “special cases” to remember in the use of its constructs.

What is the impact of Orthogonality?

[1] The orthogonality of a language has an effect on both the readability and the writability of software. [2] If a language’s rules contain fewer special cases, it is easier to learn (and therefore easier to read and write).

Explain the importance of data types

[1] must have rich set of datatypes [2] C (until recently) included no boolean type (0 was used for false and any nonzero integer for true). readablity impcat: finished = 1; finished = true;

Explain Expressiveness

The expressiveness of a programming language relates to how much code (and effort) is required to implement computations. E.g., in Java, i++ is more convenient to write than i = i + 1.