The Hong Kong Polytechnic University Faculty of Engineering

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1 The Hong Kong Polytechnic University Faculty of Engineering Programme(s) : BEng(Hons) in Transportation Systems Engineering (41481, 41481SY) BSc(Hons) in Internet and Multimedia Technologies (42477) Higher Diploma in Electrical Engineering (41373, 41373NDS) BSc(Hons) in Biomedical Engineering (47401, 47401SY) BEng(Hons) in Electrical Engineering (41470) BEng(Hons) in Mechanical Engineering (43478) BEng(Hons) in Electronic and Information Engineering (42470) BEng(Hons) in Electronic Engineering (42479) Subject : Computer Programming Subject Code : ENG2002 Session : Semester 1, 2015/2016 Date : 10 December 2015 Time Allowed : 2 hours Time : 12:30 p.m. 2:30 p.m. Subject Lecturer(s) : Dr Frank Leung, Dr Dan Wang, Dr W.L. Chan This question paper has 14 pages including this cover page. Instructions to Candidates : This question paper contains TWO (2) sections. Section A contains 36 multiple-choice questions. Follow the instructions on the paper and answer all questions by marking the answers on the Answer Sheet provided. This section carries 60 marks. Section B contains 2 questions. Follow the instructions in the questions and fill in the blanks directly on the Question Paper. This section carries 40 marks. Attachment : Answer Sheet 1

2 Section A Instruction: When specified, you may choose more than one answer otherwise, choose ONE answer for each question. Choose the answer(s) by using the Answer Sheet provided. Questions 1-12 are allocated 1 mark each Questions are allocated 2 marks each. The total marks are 60. 1) On storing a string in memory, how many byte(s) will the null character at the end of the string occupy? a) 0 byte b) 1 byte c) 2 bytes d) 4 bytes e) 8 bytes 2) To perform file I/O operations, which of the following preprocessor directive must be present in the source file? (You may choose more than one answer.) a) #include <ifstream> b) #include <ofstream> c) #include <fstream> d) e) None of the above. 3) Consider the following C++ class, where the constructor is overloaded: class Example{ public: Example(){a=b=c=1 //Constructor 1 Example(int a1){a=a1b=c=1 //Constructor 2 Example(int a1, int b1){a=a1b=b1c=1 //Constructor 3 Example(int a1, int b1, int c1){a=a1b=b1c=c1 //Constructor 4 private: int a, b, c On declaring an object by writing: Example obj(1,2,3) which constructor will be called? a) Constructor 1 b) Constructor 2 c) Constructor 3 d) Constructor 4 e) None of the above. 4) On executing the following C++ declaration statement, what is the value of b[1][0]? int b[2][2] = {{1,{34 a) 0 b) 1 c) 34 d) The statement contains error(s) and cannot be executed. e) None of the above. 5) On executing the C++ declaration statement below, which of the following choices has the same value as represented by ex? int ex[10] a) &ex[0] b) &ex[9] c) *ex[0] d) *ex e) None of the above. 6) Which of the following is not a valid C++ statement? a) enum A {me=0, you =0, them=0 b) enum A {me=1, you =2, them=3 c) enum A {me, you, them d) enum A {me, you, me e) enum A {me=2, you=1 2

3 7) Which of the following commands in Command Prompt is for showing the names of files and folders in the current folder? a) dir b) directory c) cd d) type e) chdir 8) Which of the following is the default opening mode on opening an output file? a) ios:: app b) ios:: ate c) ios:: trunc d) ios::in e) None of the above. 9) Which of the following is NOT a valid C++ statement? a) char a='a' b) char a="a" c) char a=97 d) char a='\n' e) char a='\0' 10) Which of the following C++ statement will NOT lead to a change of the value of the variable c? a) c+1 b) c=c+1 c) c+=1 d) c++ e) ++c 11) Which of the following about C++ is correct? a) A variable of bool type can have two possible values, which can be the result of a logical operation. b) A bool variable's value of false is displayed as 1 when it is streamed to the standard output. c) The result of a relational operation has a type of char. d) bool cannot be the returned data type of a function. e) None of the above. 12) What is wrong with the following C++ code? const int SIZE =5 float scores[size] //Line 2 for(int i=0 i<=size i++) //Line 3 { cout << "Enter a score\n" cin >> scores[i] a) Line 2 cannot be compiled successfully. b) In Line 3, i should be initialized to 1 instead of 0. c) The array scores[] must be of type int. d) In Line 3, "<=" should be replaced by "<". e) None of the above. Instruction: Each of the following questions below takes TWO marks. When specified, you may choose more than one answer otherwise, choose ONE answer for each question. 13) On executing the following C++ program, what will be displayed on the output screen? int main () { int x[10] = {1,2,3,4,5,6,7,8,9,10 for (int i=1i<10i++) cout<<x[i] << " " 3

4 a) b) c) d) The program cannot be compiled and executed. e) A run-time error message will prompt out. 14) On executing the following C++ program, what will be displayed on the output screen? void greeting (int x, int y) { if (x > 5) if (y < 3) cout << "Hello " else cout << "Hi " cout << "Bye " if (x > 5) { if (y < 3) cout << "Hello " else { cout << "Hi " cout << "Bye " int main () { greeting (3, 2) greeting (1, 1) a) Bye Bye b) Bye Hi Bye Hi Bye c) Bye Hi Bye d) Bye Hi Bye Bye Hi Bye e) None of the above. Consider the following C++ program and answer Questions int main() { int x = 0 for(int i=0 i<3 i++) for(int j=0 j<4 j++) x++ cout << x++ << " " << x << endl //Line A 15) On executing the above C++ program, what will be displayed on the output screen? a) 0 0 b) 0 1 c) d) e) None of the above. 16) If x++ in Line A is replaced by ++x, what will be displayed on the output screen? a) 0 0 b) 0 1 c) d) e) None of the above. 17) On executing the following C++ program, how many '*' will be displayed on the output screen? int i = 20 4

5 void iplusplus(int i) { i=i-3 for(i = 0 i <10 iplusplus(i)) { i=i+3 cout << '*' a) 1 b) 3 c) 4 d) 10 e) Unknown as the program is trapped in an infinite loop. 18) On executing the following C++ program, what will be displayed on the output screen? int power(int a, int b) { int c=0 for(int i=0 i<b i++) c *= a return c cout << power(2, 3) << endl a) 0 b) 2 c) 8 d) 9 e) None of the above. Consider the following C++ program and answer Questions #define _CRT_SECURE_NO_WARNINGS 1 class Book { char* bookname public: Book() {cout << "Book Constructor" << endl bookname = new char[10] ~Book() {cout << "Book Destructor" << endl delete [] bookname void setname(char* thename) {strncpy(bookname,thename,9) class BookStore { public: BookStore() {cout << "BookStore Constructor" << endl booklist = new Book ~BookStore() {cout << "BookStore Destructor" << endl private: Book *booklist BookStore mystore cout << "Program finished" << endl 19) Should the variable bookname of the class Book be assumed to be under public or private? a) private b) public by default c) neither pubic nor private d) public because it appears in the class e) None of the above. 5

6 20) How many bytes of memory leaks will occur on running the above program? a) 0 b) 4 c) 10 d) 14 e) The program contains error(s) and cannot run. Consider the following C++ program and answer Questions int main(){ int i enum month { JAN = 1, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC for (i = MAR i <= NOV ++i) cout << i << " " //Line A 21) On executing the above C++ program, what will be displayed on the output screen? a) b) c) d) e) None of the above. 22) If i in Line A is changed to i++, what will be shown on the output screen? a) b) c) d) e) None of the above. Consider the following C++ program and answer Questions void print(char arg[], int length) { for (short c = 0 c<length c++) //Line 4 cout << arg[c] cout << " & " char first[] = { 'e','x','a','m' char second[] = { 'e','n','g','2','0','0','2' print(first, 3) print(second, 6) 23) On executing the above C++ program, what will be displayed on the output screen? a) exa & eng200 & b) exa & en & 200 c) ex & eng200 & d) exa & g200 & e) A run-time error message will prompt out. 24) If c=0 and c++ in Line 4 are changed to c=1 and ++c respectively, what will be shown on the output screen on executing this program? a) xam & ng200 & b) xa & ng200 & c) xa & eng200 & d) xam & eng200 & e) A run-time error message will prompt out. Consider the following C++ program and answer Questions

7 #include <fstream> int position ofstream output("test.txt") output.write("do you want to", 17) //Line 6 position = output.tellp() output.seekp(position - 3) //Line 8 output.write("*pass?", 8) //Line 9 output.close() 25) On executing the above C++ program, what will be the content of the file test.txt? a) Do you want*pass? b) Do you want to *p? c) Do you want to*pass? d) you want to*pass? e) ant to*pass? 26) If Line 6, Line 8 and Line 9 are changed to output.write ("Do you want to", 18), output.seekp (pos -16) and output.write ("*pass?.",0) respectively, what will be shown on the output screen on executing the program? a) Do you want to b) Do*pass?.nt to c) Do you want t d) Do you wan e) *pass?. 27) On executing the C++ program below, what will be displayed on the output screen? int mult (int x, int y) { int result = 0 while (y!= 0) { result = result + x y = y - 1 return(result) int x = 5, y = 5 cout << mult(x, y) a) 20 b) 25 c) 30 d) 35 e) A run-time error message will prompt out. 28) On executing the C++ program below, what will be displayed on the output screen? void func(int a = 100, bool flag = true) { if (flag == true ) cout << "Flag is true. a = " << a else cout << "Flag is false. a = " << a func(200, false) a) Flag is true. a = 200 b) Flag is false. a = 100 c) Flag is false. a = 200 7

8 d) Flag is true. a = 100 e) None of the above. 29) On executing the C++ program below, what will be displayed on the output screen? void Values(int, int = 10) Values(1) Values(3, 4) void Values(int n1, int n2) { cout << n1 <<" "<< n2 <<" " a) b) c) d) A run-time error message will prompt out. e) The program cannot be successfully compiled and executed. 30) Consider the following C++ program. What should be written in Line 6 in order to convert the decimal integer value of input into a string stored in str1[]? #define _CRT_SECURE_NO_WARNINGS 1 int input = 10 char str1[3] //Line 6 std::cout << str1 //Display 10 on the screen a) _itoa(str1, input, 2) b) str1= _itoa(input) c) input= _itoa(str1) d) _itoa(input,str1,10) e) _itoa(input,str1,2) 31) On executing the C++ program below, what will be displayed on the output screen? int number=1001 int pl= 1int output=0 while (number!= 0 ) { output += number % 10 * pl number /= 10 pl *= 2 cout << output a) 9 b) 11 c) 13 d) 15 e) 1 32) On executing the C++ program below, what will be displayed on the output screen? int Array1[]={3, 7, 1, 9, 5 int Array2[5] for (int i = 0 i < 5 i++) Array2[4 - i] = Array1[i] for (int i = 0 i < 5 i++) Array1[i] = Array2[i] 8

9 cout << Array1[1] a) 1 b) 3 c) 5 d) 7 e) 9 33) On executing the C++ program below, what will be displayed on the output screen? int x=40 void fun(int x, int y) { x = 20 y = 30 int x = 10 fun(x, x) cout << x a) 10 b) 20 c) 30 d) 40 e) The program cannot be successfully compiled and executed. 34) On executing the following C++ program, what will be displayed on the output screen? int a=1, b=2 int add(int a, int b) int i = 5, j = 6 cout << add(i, j) << endl int add(int a, int b ) { int sum = a + b a = 7 return a + b a) 3 b) 11 c) 12 d) 13 e) The program cannot be successfully compiled and executed. 35) On executing the following C++ program, what will be displayed on the output screen? int func(int m = 10, int n) { int c c = m + n return c cout << func(5) a) 15 b) 10 c) A run-time error message will prompt out. d) The program cannot be successfully compiled and executed. e) None of the above. 9

10 36) On executing the following C++ program, what will be displayed on the output screen? void print(int i) { cout << i void print(double f) { cout << f int main(void) { print(5) print( ) a) b) c) d) 5500 e) 5 10

11 Section B Q1 It is assumed that the current folder contains a file named "exam.txt", which has only one line "ENG2002*exam*" as its content. The file content is shown below. Write a program that uses an array to store the content of the above file. The user needs to input the starting position of the file to read for storing to the array. The position of the first character 'E' has a value of 0. Complete the program below. (20 marks) #include // Header file for standard I/O (1 mark) #include // Header file for file I/O (1 mark) ifstream fin("exam.txt") // Open exam.txt as an input file /*Check whether the file could be opened or not. If the file cannot be opened for whatever reason, display the error message "File could not be opened." and the program ends. (3 marks)*/ if ( ) { /* File has been opened successfully. */ /* Read from the beginning to the end of the file to determine the number of characters in the file. Then, close the file. (3 marks)*/ char ch int ccount = 0 //Count the number of characters in the file while ( ) // After the above while loop, ccount stores the no. of characters in file. // Close the file // Ask the user to enter the starting position to read from the file. // Notice that the first position is position 0. int seek_position //Repeatly ask the user to enter starting position if outside 0 to ccount-1 do { //2 marks cout << "Enter the starting position to read from the file:(0-" cout << ccount-1 << "): " cin >> seek_position while ( ) ifstream fin2("exam.txt") 11

12 // Move the reading position to seek_position (2 marks) int array_size = 100 //Create a character array of size array_size in the heap (2 marks) char * parray = int aindex = 0 // Index of array /* Read from file starting from seek_position to end of file into array started from the first element. (3 marks)*/ while (fin2.get(ch)) { // Update aindex //Add a null character at the end of the string in the array. //Display the string stored in the array. (1 mark) cout << endl // Close the file (1 mark) //Release the memory for storing the array in the heap. (1 mark) Sample outputs on executing the program inside Visual Studio. (The numbers 13, -1, 0 and 11 are entered by the user.) 12

13 Q2 Build a static library for the class Arithmetic, which includes two member variables of type int and provides functions to compute addition and power for them. The project name for this static library is ariproj. The class is declared in the header file Arithmetic.h. Complete the header file and implement the member functions in the file ArithCodes.cpp for the static library below. (11 marks) Arithmetic.h // Arithmetic.h is the header file's name for the class Arithmetic class Arithmetic { public: //constructor: set the inputs to be values of the member variables //by calling member function SetNum() Arithmetic::Arithmetic(int number1, int number2) //set the inputs to be values of num1 and num2 respectively void SetNum(int number1, int number2) int GetNum1() //return the value of num1 int GetNum2() //return the value of num2 int Add() // return the sum of two member variables int Power() // return num1 to the power of num2 private: int num1 //store the first input number int num2 //store the second input number ArithCodes.cpp // Member function implementation for class Arithmetic. //End class Arithmetic //Include header file. //Constructor: set the inputs to be values of the member variables //by calling member function SetNum() Arithmetic::Arithmetic(int number1, int number2) { //Set the inputs to be values of num1 and num2 respectively void Arithmetic::SetNum(int number1, int number2) { //Return the value of num1 int Arithmetic::GetNum1() { //Return the value of num2 int Arithmetic::GetNum2() { //Return the sum of the two member variables int Arithmetic::Add() { /*Return num1 to the power of num2 (you are not allowed to call library functions for the implementation)*/ 13

int Arithmetic::Power() { What is the name of the library file created after you have built the static library project? (1 mark) A new project is opened to use the above static library.

14 int Arithmetic::Power() { What is the name of the library file created after you have built the static library project? (1 mark) A new project is opened to use the above static library. Its main() function is in the A.cpp file. Give the names of the files this project needs for using the class Arithmetic and its static library. (2 marks) Complete the program in the A.cpp file below (assuming that the appropriate files of the static library have been added to the project in the correct location) in order to obtain the sample output given. (6 marks) A.cpp #include //Include definition of the class. int n1, n2 cout<<"please enter two numbers:" cin>>n1>>n2 //Create Arithmetic object named calc with input values of n1 and n2 /*Show the 2 input nos. by calling member functions of the object.*/ cout<<"the two input numbers are: "<< cout<<" "<< <<endl //Show the sum of the 2 nos. by calling the member function of the object cout<<"the sum of two numbers is: "<< <<endl //Show the power of the 2 nos. by calling the member function of the object cout<<"the power of two numbers is: "<< <<endl Sample output (2 and 3 in the first line are entered by the user): END 14

THE HONG KONG POLYTECHNIC UNIVERSITY Faculty of Engineering. Computer Programming Closed-book Written Test 3 Date: 28 March 2009 Time: 2:30 3:30 pm

THE HONG KONG POLYTECHNIC UNIVERSITY Faculty of Engineering Computer Programming Closed-book Written Test 3 Date: 28 March 2009 Time: 2:30 3:30 pm Name: Programme Code: Student No. This test aims at assessing