Contents

• CS320/10 Questions on Subprograms and Chapter 9
• : Question 1 Define key terms
• : Question 2 Parameter Passing
• : Question 3 Arguments in C and C++
• : Question 4 Ada Subprogram parameters
• : Question 4 Pass by Name
• : Question 6 Generics
• : Question 7 Co-routines -- Deprecated
• Review

CS320/10 Questions on Subprograms and Chapter 9

Question 1 Define key terms

Here are some words used in the book. For each give the word or phrase used by a C or C++ programmer instead.

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1. Parameter, procedure, generic subprogram, program, subprogram header, subprogram definition

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Question 2 Parameter Passing

a. Describe one(1) parameter passing method.

b. Name one language which has it or had it.

c. Classify it according to its semantic mode: in, out, in-out.

Question 3 Arguments in C and C++

a. C uses "pass by value" for passing all arguments to functions. What does this mean?

b. How do the "&" and "*" operators provide a form of "pass by reference".

c. C++ added some extra parameter passing modes to those in C. What are they? How do they work?

d. What is the advantage of C++'s additional parameter passing modes over C's?

e. Rewrite the following C++ to get the same effect in C using "&" and "*" as C prefix operators:

  void flip( int & i) { i = ! i ; }

 ...

      int flop = 1;

 ...

      flip (flop);

Code with tests [ 11flip.cpp ]

Answer [ 11tester.cpp ]

Question 4 Ada Subprogram parameters

a. What is Ada's rule about the semantics of in-out parameters

b. What is wrong with Ada's rule?.

c. Give examples of Ada's keyword parameters.

d. Give advantages and disadvantages of keyword parameters.

Question 4 Pass by Name

a. Describe "pass by name" and name the language that introduced it.

b. Give an example of how "pass by name" might be used in a special way.

c. Why was it abandoned in Pascal and Algol 68?

d. Does C/C++ #define provide call by name?

e. Give a simple C/C++ program that will prove whether #define uses call by name or not!

Question 6 Generics

a. Name two(2) examples of languages that allow programmers to define generic subprograms.

b. Show how to write a generic subprogram that returns the larger of two values in one of these languages.

c. What are the advantages of generic subprograms?

Question 7 Co-routines -- Deprecated

a. How do co-routines differ from sub-programs.

b. Name one language that provides co-routines.

. . . . . . . . . ( end of section CS320/10 Questions on Subprograms and Chapter 9) <<Contents | End>>

Review

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