2. Declare a pointer variable named ptr to an integer. ANSWER: int *ptr;

Transcription

1 Chapter 9 Short Answer 1. A is the memory address of a variable. ANSWER: pointer 2. Declare a pointer variable named ptr to an integer. ANSWER: int *ptr; 3. In the statement cout << *p1;, the * is called the ereferencing operator 4. The & operator is called the ANSWER: address of operator 5. Write the code that assigns to p1 (an integer pointer variable) the pointer to a dynamically created integer. ANSWER: p1 = new int; 6. Dynamic variables are created at ANSWER: run time 7. Dynamic variables are created from the. ANSWER: freestore or heap 8. Write the code to return the dynamic memory pointed to by p1 to the freestore. elete p1; 9. The size of a dynamic array is defined at ANSWER: run-time 10. Write the code to declare a dynamic array of strings (use the string pointer variable p1) that has as many elements as the variable arraysize. ANSWER: p1 = new string[arraysize]; 1

2 Short Answer 1. The keyword defines a structure type definition. ANSWER: struct 2. A structure definition ends with the closing brace and a. ANSWER: semicolon 3. A structure variable is a collection of smaller values called values ANSWER: member 4. When a structure contains another structure variable as one of its members, it is known as a. ANSWER: hierarchical structure 5. When several items (variables or variables and functions) are grouped together into a single package, that is known as. ANSWER: (data) encapsulation 6. The double colon (::) is known as the operator. ANSWER: scope resolution operator 7. Who can access private members in a class? ANSWER: only other members of the class 8. A member function that allows the user of the class to find out the value of a private data type is called a. ANSWER: accessor function 9. A member function that allows the user of the class to change the value of a private data type is called a. ANSWER: mutator function 10. If you have a class with a member function called display(ostream& out), that will send the values in the class to the parameter stream, and you need to call that function from within another member function, how would you call it to print the data to the screen? isplay(cout); 11. What can a constructor return? ANSWER: nothing 12. The name of a constructor is ANSWER: the name of the class 1

3 13. The constructor of a class that does not have any parameters is called a constructor. efault 14. In the following class constructor definition, the part of the header starting with a single colon is called the. BankAccount::BankAccount(): balance(0), interest(0.0) ANSWER: initialization section 15. A class in which modifications to the implementation appear to be invisible to the user of the class is known as. ANSWER: an Abstract Data Type (ADT) 16. A member function that gets called automatically when an object of the class is declared is called a. onstructor Multiple Choice 1. In a structure definition, the identifiers declared in the braces are called a. classes b. structs c. member names d. variables 2. You specify an individual member of a struct by using a. the assignment operator b. an ampersand c. an underscore d. The dot operator 3. To assign values to a structure variable, you use the a. equals operator b. assignment operator c. extraction operator d. less than operator 4. What is wrong with the following structure definition? struct MyStruct 2

4 int size; float weight; a. Nothing b. Can not have mixed data types in a structure c. missing semicolon d. Braces are not needed. 5. Given the following strucure definitions, what is the correct way to print the person's birth year? struct DateType int day; int month; int year; struct PersonType int age; float weight; DateType birthday; PersonType person; a. cout << person.birthday.year; b. cout << year; c. cout << birthday.year; d. cout << peson.year; ANSWER: a 6. Given the following strucure definition, what is the correct way to initialize a variable called today? struct DateType int day; int month; int year; a. DateType today(1,1,2000); b. DateType today = (1,1,2000); c. DateType today = 1,1,2000); 3

5 d. DateType today = 1,1,2000,0); or c 7. When defining a class, the class should be composed of the kind of values a variable of the class can contain, and a. member functions for that class b. the keyword private c. other class definitions d. nothing else ANSWER: a 8. Which of the following is the correct function definition header for the getage function which is a member of the Person class? a. int getage(); b. int getage() c. int Person:getAge() d. int Person::getAge() 9. Given the following class definition and the following member function header, which is the correct way to output the private data? class Person void outputperson(ostream& out); int age; float weight; int id; ; void Person::outputPerson(ostream& out) //what goes here? a. out << person.age << person.weight << person.id; b. out << person; c. out << age << weight << id; d. outputperson(person); 10. Why do you want to usually make data members private in a class? a. so that no one can use the class. b. ensure data integrity c. provide data abstraction. d. provide information hiding. 4

6 e. B and D f. B, C and D ANSWER: f 11. A member function of a class should be made private a. always b. only if it will never be used c. if it will only be used by other members of the class d. never, it is illegal to make a member function private. 12. A member function that allow the user of the class to change the value in a data member is known as a. a mutator function b. a mutation c. a manipulator function d. an accessor function ANSWER: a 13. A Member function that allows the user of the class to see the value in a data member is known as a. a mutator function b. a mutation c. a manipulator function d. an accessor function 14. If you design a class with private data members, and do not provide mutators and accessors, then a. The private data members can still be accessed from outside the class by using the & operator b. The data can not be changed or viewed by anyone. c. None of the above d. A and B 15. A class member function that automatically initializes the data members of a class is called a. the init function b. an operator c. a constructor d. a cast 16. If you have a class named mypersonclass, which of the following correctly declare a constructor in the class definition? a. mypersonclass::mypersonclass(); 5

7 b. mypersonclass(); c. init(); d. cast(); 17. given the following class definition, how could you use the constructor to assign values to an object of this class? class CDAccount CDAccount(); CDAccount(float interest, float newbalance); float getbalance(); float getrate(); void setrate(float interest); void setbalance(float newbalance); float balance, rate; ; and the following object declaration CDAccount myaccount; a. myaccount = CDAccount(float myrate, float mybalance); b. myaccount = CDAccount myrate, mybalance; c. myaccount = CDAccount[myRate, mybalance]; d. myaccount = CDAccount(myRate, mybalance); 18. Given the following class definition, what is missing? class ItemClass ItemClass(int newsize, float newcost); int getsize(); float getcost(); void setsize(int newsize); void setcost(float newcost); int size; float cost; ; a. nothing b. a default constructor c. accessor functions d. mutator functions 6

8 19. Given the following class definition, how would you declare an object of the class, so that the object automatically called the default constructor? class ItemClass ItemClass(); ItemClass(int newsize, float newcost); int getsize(); float getcost(); void setsize(int newsize); void setcost(float newcost); int size; float cost; ; a. ItemClass() myitem; b. ItemClass myitem(1, 0.0); c. ItemClass myitem; d. ItemClass myitem(); e. You can not do this 20. A data type consisting of data members and operations on those members which can be used by a programmer without knowing the implementation details of the data type is called a. an abstract definition type b. an available data type c. an abstract data type d. a primitive data type 21. Which part of the ADT tells the programmer using it how to use it? a. the implementation b. the interface c. the abstractness d. the scope resolution 22. If you are designing a class for an ADT, you can tell if the class is an ADT if a. when you change the implementation of the class, none of the rest of the program needs to change. b. when you change the interface of the class, nothing else needs to change. 7

9 c. you change the privte part and the rest of the program using the ADT does not compile. d. everything must be changed. ANSWER: a 23. Developing an ADT means that the user of your class does not have to know the details about how the class is implemented. This is known as a. interface b. implementation c. testing and debugging d. information hiding 24. Given the following class, what would be the best declaration for a mutator function that allows the user of the class to change the age? class Wine Wine(); int getage(); float getcost(); int age; float cost; a. int getage(int newage); b. Wine(); c. void setage(); d. void setage(int newage); 8

10 Chapter 11 1 Multiple Choice 1. How many members (data and functions) does the following class have? class Rational Rational(); Rational(int numer, int denom); Rational(int whole); int getnumerator(); int getdenominator(); friend void display(ostream& out, const Rational& value); int numerator; int denominator; ; a. 2 b. 6 c. 5 d. 7 e Who can access private data in a class? a. members of the class b. friends of the class c. everyone d. a and b e. no one 3. Given the following class, which is the correct function header for the display function? class Rational Rational(); Rational(int numer, int denom); Rational(int whole); int getnumerator(); int getdenominator(); friend void display(ostream& out, const Rational& value);

11 Chapter 11 2 int numerator; int denominator; ; a. friend void display(ostream& out, const Rational& value) b. void display(ostream& out, const Rational& value) c. void Rational::display(ostream& out, const Rational& value) d. friend void Rational::display(ostream& out, const Rational& value) 4. If we have a full selection of accessor and mutator functions, why would we have friend functions? a. You should not have them b. More efficient access to the private data members. c. The friend function must call the accessor or mutator functions anyway. d. none of the above 5. Why should you generally pass an object of the class to a friend function as a reference parameter? a. If the friend function changes the values of the data member(s). b. If the friend function will not change the values of the data member(s). c. It is more efficient to pass the object by reference. d. A and B e. A and C ANSWER: e