Question 1

A constructor is like a function.It can return any type value needed.

Accepted Answer

A constructor is a special function that is used to create an instance of a class. It does not return any value, but instead initializes the properties of the object being created.

Question 2

A constructor is a special kind of member function.It is automatically called when an object of that class is declared.

Accepted Answer

A constructor is automatically called when an object is declared. It is used to initialize values and set up the object's initial state.

Question 3

A constructor usually terminates by falling off the end of its block,but a return statement is permitted if there is no argument add following the word return..

Accepted Answer

A constructor usually terminates by falling off the end of its block, but it is also permitted to have a return statement with no argument following it. However, this is not recommended as it can cause confusion and is not necessary in most cases.

Question 4

Assignment behaves essentially the same for vectors as for arrays.

Accepted Answer

Vectors in C++ are dynamic arrays that can resize themselves automatically when an element is added or removed, and they provide a lot of member functions for managing these operations. Arrays, on the other hand, have a fixed size that must be specified at compile time and do not offer built-in methods for resizing or easy management.

Question 5

A local class and a nested class are the same thing.

Accepted Answer

A local class is a class that is defined inside a block of code, such as a method, whereas a nested class is defined inside another class. They are similar in that they are both inner classes, but they are not the same thing.

Question 6

If v is a vector and i is an int variable,then in the following the value of i can be any nonnegative int value:
v[i] = i;

Accepted Answer

The answer of If v is a vector and i...

Question 7

The set of integers ranging from -MAXINT to MAXINT make up the int data type.

Accepted Answer

The range of the int data type is dependent on the programming language and machine architecture. It is not necessarily limited to the range between -MAXINT and MAXINT. However, in some languages, this range may indeed be used for the int data type.

Question 8

A class may not have another class type object as a member.

Accepted Answer

It is possible for a class to have another class type object as a member, known as composition or aggregation.

Question 9

A constructor is always named construct with class name attached.If the class is Foo,then the constructor name is constructFoo.

Accepted Answer

This statement is false. The name of the constructor in a class is always the same as the name of the class. For example, if the class is named Foo, then the constructor name would be Foo().

Question 10

It is valid to initialize member variables in a class on the same line in which the variable is declared.For example,the following sets xx to 1000:
class A
{
public:
A(){}
private:
int xx = 1000;
};

Accepted Answer

This is a valid way to initialize member variables in a class since C++11.

Question 11

A static variable of a class cannot be changed.

Accepted Answer

A static variable of a class can be changed. The keyword 'static' means that the variable is associated with the class rather than a specific instance of the class, but it doesn't mean that the value of the variable cannot be modified. Static variables can be modified using the class name followed by the dot operator, like ClassName.variableName = newValue.

Question 12

The keyword static is used in a static function declaration in a class but not in the function definition.

Accepted Answer

The keyword static is only needed in the function declaration inside the class to indicate that it is a static function. It is not needed in the function definition outside of the class.

Question 13

size and capacity of a vector are two names for the same thing.

Accepted Answer

Size refers to the number of elements currently stored in the vector, while capacity refers to the amount of space allocated for the vector, which can potentially hold more elements than its current size without requiring reallocation.

Question 14

The functions or data members declared in the private: section of a class can be accessed only in the definition those functions declared in that class.Note that friend functions are also declared (but not defined)in the class to which they are friends,so they also have access to private as well as public members.

Accepted Answer

The private members of a class can only be accessed within the class definition, including the definition of functions declared in the class. Friend functions, while not defined in the class, are declared within it and therefore have access to private members.

Question 15

Any use of the keyword const is a promise to the compiler,and a request to the compiler to enforce the promise.What promises?

Accepted Answer

When using the keyword const, we promise to the compiler that the value of the declared variable will not change during the program execution. It is a request to the compiler to enforce this promise by throwing an error if any attempt is made to modify the constant value.

Question 16

Vector assignment is well behaved.

Accepted Answer

Vector assignment in most programming languages is well behaved, since it simply copies the memory address of the vector rather than copying the entire vector's contents. This makes it efficient and avoids potential issues with deep copying large or complex vectors.

Question 17

You can write a class that is useful with all its constructors in the private section.

Accepted Answer

The answer of You can write a class that is...

Question 18

A constructor can be called implicitly or explicitly.(Implicitly means the compiler did it for you. )In the interest of uniformity in answers,please use class A;for your examples.

Accepted Answer

This statement is true. A constructor can be called implicitly by the compiler or explicitly by the programmer.

Question 19

Inline functions are always more efficent than noninline functions.

Accepted Answer

Inline functions can often lead to increased code size, which can affect efficiency, particularly in large programs. Noninline functions, on the other hand, can be optimized by the compiler to reduce function call overhead, leading to better performance. Therefore, it is not always true that inline functions are more efficient than noninline functions.

Question 20

It is legal to call a constructor as a member function of an object of a class,as in
class A
{
public:
A(){}
A(int x,int y):xx(x),yy(y){}
// other members
private:
int xx;
int yy;
};
int main()
{
A w;
w.A(2,3);// Is this legal?
}

Accepted Answer

It is not legal to call a constructor as a member function of an object of a class. Constructors are meant to be called only during object creation, not afterwards. Attempting to call a constructor as a member function can lead to undefined behavior.

Quiz 7: Constructors and Other Tools