Deck 16: Templates

Question 1

In implementing class template member functions,the functions are themselves templates.

Answer 1

True

Question 2

The template prefix can be written template or template with the same results.

Answer 2

True

Question 3

What if anything is wrong with the following code?
template
class A
{
public:
A();
...
private:
...
};
A::A()
{
//...
}

Answer 3

The constructor A is a template function,hence it requires a template prefix:
template
A::A()
{
...
}

Question 4

A non-template class can be derived from a class template instantiation.

Question 5

Templates can make available to the programmer the generality of algorithms that implementation with specific types conceals.

Question 6

Templates allow only parameterized types for class templates

Question 7

It is preferable to separate implementation and specification in software.Hence,it is preferable to place a template class definition in a "header" file,the template implementation of the member functions in an implementation file.The implementation should be compiled separately and linked to the application.

Question 8

To instantiate and call,a template function requires special syntax.

Question 9

What problems with templates have you encountered,or have you been warned about by your instructor,with regard to your compiler's template facility?

Question 10

In the template prefix,template the keyword class means that the type parameter T must be of class type.

Question 11

It is possible to have more than one type parameter in a template definition.

Question 12

Templates provide an overloading of the function for every possible type that is consistent with the use in the template.

Question 13

Templates allow only parameterized types for functions.

Question 14

A class template can be derived from a non-template class.

Question 15

In the implementation of a class template function,the class name before the scope resolution operator is just the class name,with no additional syntax.

Question 16

Suppose the swapValues template is instantiated as follows:
int x = 2,y =3;
swapValues(x,y);
// use x and y
x = 4;y =5;
swapValues(x,y);
// use x and y
The compiler generates code for two copies of the swapValues template.

Question 17

In the template prefix,template the identifier T is called a value parameter.

Question 18

In writing a class template,the function declarations within the class require special placement.

Question 19

A class template cannot be derived from a class template.

Question 20

With regard to programming usage,consistency in coding is more important than optimality.

Question 21

What is wrong with the following function template (Other than the fact that it really does almost nothing)?
template
int f( int & x )
{
return x;
}
int main()
{
int y = 3,z;
z = f(y);
}

Question 22

Discuss briefly,indicating whether mostly true or mostly false and justify:
A friend of a class is used exactly the same for template and non-template classes.

Question 23

There are three absolute value functions defined in various header files.These are abs,fabs,and labs.Write a template function that subsumes all three of these functions into one template function.

Question 24

Define or characterize the template facility for C++.

Question 25

Which of the following template function definitions and invocations will not compile,if any? If not,why not?
Assume that classes have been declared with appropriate default constructors and assume that
//a)
template
A func( A x,A y){ return A();}
int main()
{
U u1,u2,u3;
u2 = func(u2,u3);
}
//b.
template
B func(){ return 1;}
int main()
{
T t;
t = func();
}
//c.
template
void func(C x,int * y){}
int main()
{
T t;
int i;
func( t,&i );
}
//d.
template
void func(D x,E y){}
int main()
{
T t;
U u;
func ( t,u );
}

Question 26

Describe a strategy for writing template functions.

Question 27

Describe the syntax for a function template.