UNIVERSITY OF MALTA FACULTY OF INFORMATION AND COMMUNICATION TECHNOLOGY Department of Computer Information Systems

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1 UNIVERSITY OF MALTA FACULTY OF INFORMATION AND COMMUNICATION TECHNOLOGY Department of Computer Information Systems May/June 2015 Assessment Session CIS1111 C Programming for Engineers X June 2015 Examination Instructions This is an open book examination. You may use any hardcopy written reference material, including hard copy course notes, textbooks and dictionaries with any annotations. Digital equipment is not permitted. This paper contains 2 Sections. Answer all questions from Section A and any two questions from Section B. Page 1 of 7

2 SECTION A ANSWER ALL QUESTIONS QUESTION 1. This is a compulsory question related to C programming constructs. You are only required to write code snippets as shown in the example below: Sample Question: Write code that outputs on the screen fifteen asterisks on the same line. Sample Answer: for(i = 0;i < 15;i++) printf( * ); a) Using only one printf statement, write the required code to produce the following output: All I can say is, Damn the exam! - William Shawcross, The Queen Mother: The Official Biography b) A variable of type double named g holds the value Write a statement to output on the screen the contents of g in two decimal places. c) Write the required code to output on separate lines the square numbers of the numbers between 1 and n, where n is a variable of type int. d) Write the required code in order to ask the user to enter the characters Y or N as an answer for a Yes/No question. The input should not be case sensitive (i.e. y or n are also valid) however any other character should not be allowed. If the user enters an invalid character then the user should be asked to re-enter the character. This should be repeated until a valid character is entered. e) A variable ch of type char contains a digit. Write the required code to convert the contents of this variable to an actual integer. The integer should be stored in a variable num of type int. [3 marks each] QUESTION 2. This is a compulsory question. You are required to provide a descriptive answer for each question. a) The aim of the program below is to display the contents of array days. int i; char days[7][4] = Mon, Tue, Wed, Thu, Fri, Sat, Sun ; for(i = 1;i <= 7;i++) puts(days[i]); Page 2 of 7

3 When the above program is executed, something goes wrong. Answer the following questions: i. What is wrong with the above code? ii. iii. What is actually outputted on the screen? Write a code snippet to show how the above code can be altered in order to give the correct output. [2 marks each] [6 Marks] b) When the following program is executed: #include <stdio.h> char quote[39] = "'What's normal anyways?' - Forrest Gump"; puts(quote); The following output is given: i. What is wrong with the above program? ii. Write a code snippet to show how the above code can be corrected. [3 marks + 2 marks] [5 Marks] c) When executed, what will this program output? float avg = ( ) / 3; printf("%f\n",avg); [4 Marks] QUESTION 3. This is a compulsory question. You are required to write a code snippet to answer this question. The following incomplete code illustrates a program that consists of an array holding 16 sorted names. The last part of the program displays these names on the screen. You are required to write code in the part which is being marked with an empty rectangle so that the names will be shuffled. When the names are outputted they should not be outputted in ascending order but in a random order. You are only required to write in you examination script the missing code and not the entire program. Page 3 of 7

4 #include <stdio.h> #include <time.h> int main (void) int i, j, k; char temp[20]; char names[16][20] = "Anne", "Carmen", "David", "Jesmond", "John", "Joseph", "Karen", "Kevin", "Manuel", "Maria", "Matthew", "Michaela", "Paul", "Sandra", "William", "Yilenia"; for(i = 0;i < 16;i++) puts(names[i]); return 0; [5 marks for the algorithm used for the solution] [5 marks for correct implementation] [5 marks for overall program correctness] QUESTION 4. This is a compulsory question related to pointers. You are required to provide a descriptive answer for parts a and b and a code snipped for part c. a) Explain the meaning of the following three lines of code: int *pnum; int num = 28; pnum = &num; [1 Mark for each line of code] [3 Marks] b) The memory sketch below illustrates what happens when the program written below is executed. (It is assumed that variable pnum is stored at memory location 102). int *pnum; pnum = (int*)malloc(sizeof(int)); *pnum = 27; printf("variable pnum is pointing to location %d ",pnum); printf("that is holding value %d.\n",*pnum); Page 4 of 7

5 When executed, what will the othe program output (with respect to the memory sketch)? [2 marks for each variable output] [4 Marks] c) An array numbers of type int has a length of 5. Using pointer techniques (do not use array indexing with [..]) and a for loop, write the required code in order to display the contents of this array on the same line, separated by a comma (,). You are not required to write the whole program but only the missing part (shown as an empty rectangle) shown in the code snippet below: #include <stdio.h> int i; int numbers[5] = 76, 34, 56, 14, 28; int *ptrnumbers; printf("\n"); [8 Marks] Page 5 of 7

6 SECTION B ANSWER ANY 2 QUESTIONS FROM THIS SECTION QUESTION 5. This is an optional question. You are required to write a complete C program by answering the given questions. The program that you are required to implement is related to single linked lists, recursive functions and the Fibonacci sequence. You are required to create a linked list and fill it with the Fibonacci sequence up to a number indicated by the user. The program should then display a menu that allows the user to either output the Fibonacci value for a particular position or display the whole list. By answering the following questions, you will be able to implement this program: a) Define the struct that is required to represent the nodes for the required linked list and also declare all the global variables that might be required for this program. [2 Marks] b) Implement a recursive function that accepts a (positive) integer parameter and returns the Fibonacci value for that number. (Hint: The Fibonacci sequence is computed as follows: F 0 = 0, F 1 = 1, F n = F n-1 + F n-2 ) [5 Marks] c) Write a function to add a Fibonacci number to the list. d) Write a function to display all the Fibonacci numbers that are stored in the list. [2 Marks] [3 Marks] e) Write a function to display on the screen the Fibonacci value of a particular number by reading it from the list. [3 Marks] f) Write the main function for this program. When the program starts it should first ask the user to enter up to which number s/he wishes to generate the Fibonacci sequence. Then the program should generate the Fibonacci sequences and display the following menu: 1. Show the Fibonacci List 2. Display the Fibonacci value of a particular number 3. Exit [5 Marks] [Total of 20 Marks] QUESTION 6. This is an optional question related to looping structures. To answer this question you are required to write three separate code snippets. In C and in other imperative and object oriented languages there are three basic types of loops. Although there are three types of loops, in theory it is possible to do anything with only one type of loop. This is obviously not recommended. In this question you are required to show that this is possible by providing three different answers each time useing a different type of loop. Page 6 of 7

7 QUESTION: Write a program which will find the average of a set of positive numbers entered by the user. There is no limit to how many numbers the user can input, in fact an end-ofdata marker such as -1 should be used to stop the program from asking the user to enter more numbers. [3 marks for correct identification of loops] [4 marks for each correct loop implementation] [5 marks for overall correctness of the solutions] [Total of 20 Marks] QUESTION 7. This is an optional question. You are required to write a complete C program. Write a program (possibly using a greedy algorithm) in which the user would enter an integer amount of money in Euros. The program should then display on the screen the minimum number of 500, 200, 100, 50, 20, 10, 5, 2 and 1 notes and coins that would make up the entered amount. [Note: To get full marks in this question, you are not only required to provide a correct working solution, but you are required to provide a neat solution preferably using only few lines of code and statements.] END OF PAPER [8 marks for the technique used to solve the problem] [5 marks for the correct use of programming constructs] [7 marks for overall correctness] [Total of 20 Marks] Page 7 of 7