Chapter 9 Flashcards by Stephan Smit

What are the 2 fundamental abstraction facilities?

Process abstraction
Data abstraction

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Fundamentals of the subprograms

Single entry point.
Calling program is suspended during subprogram execution
Control returns to caller after execution of sub program

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What is a subprogram definition?

(the entire function) Defines interface(how to use) + actions(What is does) of a subprogram

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What is a subprogram header?

1st part of the subprogram definition ( name, type, parameters

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Example of a subprogram header:

int doSomething(int first){…}

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Formal vs actual parameters:

Formal = “dummy” (int first)
Actual = (12)

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What is a parameter profile/signature?

Parameters + types of the function
(length: int, width : int, height : int)

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What is a protocol?

Parameter profile + return type
int calc(x: int, y: int);

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What is a subprogram declaration?

The entire function

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Prototype function example:

void foo(int,float);

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What is a positional parameter?

Bind actual to formal parameters by position

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What is the advantage of positional parameters?

Safe and effective

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Disadvantage of positional parameters?

Hard to read + if you switch 2 numbers, the function will still run perfectly

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What is keyword parameters?

Bind to the names of formal parameters

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Example of keyword parameters:

add(first = 10, second = 12, third = 3)

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Advantage of keyword parameters?

Any order
Avoid parameter correspondence errors

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DisAdvantage of keyword parameters?

Writeability

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What are default parameters?

When you assign a value to the parameter in the declaration. If no value is passed in for that parameter then it get assigned the default value

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Why must default parameters be last?

How else would you know which parameter is which/

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How many parameters are there in variable number parameter?

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How are variable number of parameters processed?

Like a list

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Difference between functions and procedures?

Procedures give results by modifying.
Functions give results by returning

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Do procedures have return values?

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Advantage of stack-dynamic local variables:

recursion + flexibility

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Disadvantage of stack-dynamic variables

cost of Time for allocation, initialization and de allocation

In most languages local variables are ....?

stack-dynamic

What are the 3 modes for parameters?

In mode (receive data from actual parameter) out mode (send data to parameter) inout(send + receive data from actual parameter)

What are the 2 ways data transfer can take place?

Physical copy Transmit access path

5 models for parameter passing:

Pass-by-value Pass-by-result Pass-by-value-result Pass-by-reference Pass-by-name

How does pass-by-value work?

Copy Or transmit access path(not recommended cause of protection)

Disadvantage of Pass-by-value?

(copying) additional storage (access path) accesses cost more

What mode is pass by value?

In Mode

How does pass-by-result work?

Value of formal parameter is used to change actual parameter

What mode is pass by result?

Out mode

What is a disadvantage of pass by result?

Extra storage + copy operation

What is pass-by-value-result?

Combines pass by value and pass by result

What is pass-by-value-result drawbacks?

Both the drawbacks of pass by value and result

What mode is pass-by-value-result?

inout

What is pass by reference?

Pass a access path

How do you pass by reference?

With a reference or pointer

What is the advantage of pass by reference?

Efficiency ( no copying + duplicate storage)

What mode is pass by reference?

inout

What is the disadvantage of Pass by reference

Slower access to formal parameters Side effects

What mode is pass by name

inout

How does pass by name work?

It uses textual substitution All formal parameters are are replaced by appropriate actual parameter

How does pass by assignment work?

Assign actual parameter to formal parameter

What are the benefits of parameter type checking?

Increased reliability

Can multidimensional arrays be passed in as parameters?

Yes, but mapping function must know size of all dimensions in the multidimensional array except the first

How is a multidimensional array used as a parameter in C++?

void fun(int matrix[][10]){...} (Dont need to know 1st dimension)

What is a disadvantage of multidimensional arrays as parameters?

No writing flexible subprograms Must have exact dimensions

How can we by pass no flexibility and rigid structure?

Pass array as a pointer, and dimensions as parameters

What is the disadvantage of passing an array as a pointer, and the dimensions as separate parameters

Error-prone Less readable

What is the most important for designing parameter passing

Efficiency 1-way or 2-way

What parameter passing is best for structures of significant size?

Pass by reference

What is a method pointer in C++?

A pointer to a function but you dont know which function. float myFunc(float a, int b){..} float(*ptr)(float,int) = myFunc;

What is a delegate in C#?

Similar to a method pointer in C++

what is shallow binding when passing subprograms as parameters?

Bind subprogram's referencing environment to the one of the caller ( use callers referencing environment)

For what type of languages is shallow binding normally used for?

Dynamic scoped languages

what is deep binding when passing subprograms as parameters?

Use referencing environment of when it is passed in (if a variable is overwritten when it is passed as a parameter use that new parameter)

what is ad-hoc binding when passing subprograms as parameters?

fun sub3(){ var x = 3; call sub4(sub2) } Since sub2 was passed to sub4 in sub 3... It will have sub3's referencing environment

What is a overloaded subprogram?

Same name as another subprogram in the same referencing environment

How do you distinguish overloaded subprograms?

It has a unique protocol

What is a generic/polymorphic subprogram?

Different parameter types in different calls template T add(T a, T b){} (this is generic)

What is ad hoc polymorphism?

Function overloading

What is parametric polymorphism?

A subprogram that takes a generic parameter template in c++

When are subprogram versions created for C++?

At compile time

When are Java generic methods instantiated?

At run time

How many times are Java generic methods instantiated?

Once

What happens when casts are not automatically in Java?

Any type errors will only be detected at runtime

How does a wildcard look like for type declaration in java?

Usually used in the sense List l

What does the wildcard in java type declaration mean?

Any type of object

How do you reduce side effects?

Make parameters in-mode only

What is a closure in JS?

An anonymous function return function(y){return x + y} if x = makeAdder(5) and adder returns this then x becomes a function

What is a coroutine?

A subprogram with multiple entry points Controls the entry points itself

What is symmetric control in the context of coroutines?

Caller + callee coroutine exist on a more equal basis

What is a coroutine call called?

A resume

What is quasi-concurrent execution in coroutines?

They appear to run at the same type but actually they are interleaved on a single thread