Chapter 2

Concept of Programming Languages by Robert W. Sebesta Answer

Review Questions

1. In what year was Plankalkul designed ? in what year was that design published ?

Plankalkul is a computer language designed for engineering purporses by Konrad Zuse between 1943 and 1945. 
It was the first high-level non-von Neumann  programming language to be designed for a computer. Also, notes survive with scribblings about such a plan calculation dating back to 1941.  It was published in year 1972.

2. Mention an interesting feature of Zuse’s programs.

It includes assignment statements, subroutines, conditional statements, iteration, floating point arithmetic, arrays, hierarchical record structures, assertions, exception handling, and other advanced features such as goal-directed execution.

3. What does Plankalkul mean ?

Plan Calculus (Plankalkul word is from Germany).

4. Speedcoding was invented to overcome two significant shortcomings of the computer hardware of the early 1950s. What were they ?

Speedcoding is a floating point three-address system which greatly simplifies programming, and checking out a program. Speedcoding provides convenient input-output operations, built-in checking, easy loading and printing. Therefore, Speedcoding reduces programming and testing expenses considerably. These expenses are often a large part of the cost of operating a computing installation. Thus Speedcoding is economical as well as convenient to use.

6. What hardware capability that first appeared in the IBM 704 computer strongly affected the evolution of programming languages ? Explain why.

The hardware has both indexing and floating-point instructions. It affects strongly because floating-point operations were simulated in software, and this operation is very time-consuming and the interpretation and the simulation of indexing were insignificant.

7. Who developed the Speedcoding system for the IBM 701 ?

The language was developed by John Backus in 1953 for the IBM.

10. What was the most significant feature added to Fortran 1 to get Fortran II ?

It added independent compilation of subroutines. Without it, any change in a program required the entire program to be recompiled.

11. What control flow statements were added to Fortran IV to get Fortran 77 ?

if-else

12. Which version of Fortran was the first to have any sort of dynamic variables ?

Fortran 90

13. Which version of Fortran was the first to have character string handling ?

Fortran 77

18. What two professional organization together designed ALGOL 50?

IFIP WG 2.1 was formed as the body responsible for the continued support and maintenance of the ALGOL 60 programming language. The Modified Report on the Algorithmic Language ALGOL 60 and the ALGOL 68 programming language were produced by WG 2.1.

19. What was the goal for developing C?

to provides constructs that map efficiently to typical machine instructions, and therefore it has found lasting use in applications that had formerly been coded in assembly language, most notably system software like the Unix computer operating system.

46. What is the primary application for Objective C?

Objective-C is the primary language used to write Mac software

57. What data types does Java support ?

Java supports both classes and primitive types.

58. What characteristic does C++ share with .NET?

C++ can share library in .NET

55. What is the relationship between Javascript and PHP, in terms of their use?

Javascript is executed in client side, while PHP is executed in server-side. Javascript is used mainly in design user interface of a website.

69. Where are the .jsp files executed ?

.jsp files are executed by a servlet container.

Problem Set

1. What features of Fortran IV do you think would have had the greatest influence on Java if the Java designers had been familiar with Fortran ?

Logical data type and logical boolean expression, with this, we can create simple version of the complex compile, and link processes of earlier compilers.

2. Determine the capability of Short Code, and compare them with those of a contemporary programmable hand calculator.

Short Code consists of coded version of mathematical expression that was to be evaluated. Short code can be used to code many equations such as power, square roots, addition, subtraction, division but there is no multiplication code. Short code was able to be implemented into UNIVAC I computer. In the other hand contemporary programmable calculator was able to do multiplication with its embedded programming language.  So with the contemporary calculator people can solve arithmetic problem easier than using the Short Code but it is more difficult to do further improvement to the programmable hand calculator than to the Sort Code.

3. Write a short history of Fortran 0, Fortran I, Fortran II and Fortran IV systems.
Fortran 0

- Fortran 0 was described in the IBM report titled “The IBM Mathematical FORmula TRANslating System : FORTRAN”. It was boldly stated that FORTRAN would provide the efficiency of hand-coded programs and the ease of programming of the interpretive pseudocode systems.
Fortran I

- Fortran I was described in October 1956. It included input/output formatting, variable names of up to six characters, and user-defined subroutines. The early success of Fortran I was shown in results of a survey made in April 1958. Most of the code written for 704s was being written in Fortran, despite skepticism of most programming world a year earlier
Fortran II

- Fortran II compiler was distributed on 1958. It fixed many bugs in the Fortran I and added some significant features to the language, the most important being the independent compilation of subroutines. Few years after, it also added support for double precision and complex data types 

- Fortran IV was developed in 1961 and released in 1962. It became the most used programming language of its time. IT contains many improvements from Fortran II, like explicit type declarations for variables, logical if construct and capability of passing subprograms as parameters to other subprograms

5. Which of three original goals of the Fortran design committee, in your opinion, was most difficult to achieve at that time?

The goal to provide an efficient of hand coded program was look like be the most difficult to achieve because at that time the computer had very small memory and were slow. It would be ineffective to make an hand coded complex program that kind of computer.

6. Which characteristics of programming languages do you think are the most important and why ?

I think, the most important is reliability. A programming language must be reliable, it needs to check every line of code is running properly without having memory leak.

7. LISP began as a pure functional language but gradually acquired more and more imperative features. Why?

 LISP acquired more and more imperative feature because repetitive processes can be specified with recursive function calls, making iteration (loops) unnecessary. That basic concept of functional programming makes it significantly different from programming in an imperative language.

10. Outline the major development in ALGOL 60.

• The concept of block structure was introduced. This allowed the programmer to localize parts of programs by introducing new data environments, or scopes.

• Two different means of passing parameters to subprograms were allowed: pass by value and pass by name.

• Procedures were allowed to be recursive. The ALGOL 58 description was unclear on this issue. Note that although this recursion was new for the imperative languages, LISP had already provided recursive functions in 1959.

• Stack-dynamic arrays were allowed. A stack-dynamic array is one for which the subscript range or ranges are specified by variables; so that the size of the array is set at the time storage is allocated to the array, which happens when the declaration is reached during execution.

14. What are the arguments both for and against the idea of typeless language? 

Typeless language is less powerful to solve a specific problem such as for business or for Website but in the other hand typeless language provides a simplicity in the making of a common program and by using typeless language the program that is written can be run in almost all system platform. With typeless language programmer doesn’t need to know many kind of syntax from many kind of different programming language.