BSc.(Hons.) Business Information Systems, BSc. (Hons.) Computer Science with Network Security, BSc.(Hons.) Software Engineering

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1 BSc.(Hons.) Business Information Systems, BSc. (Hons.) Computer Science with Network Security, BSc.(Hons.) Software Engineering Cohorts BIS/04 Full Time - BCNS/04 Full Time SE/04 Full Time Examinations for / Semester 2 MODULE: STRUCTURED PROGRAMMING MODULE CODE: BISE 060 Duration: 2 Hours 15 Minutes Instructions to Candidates: 1. Answer any 3 questions. 2. Questions may be answered in any order but your answers must show the question number clearly. 3. Always start a new question on a fresh page. 4. All questions carry equal marks. 5. Total marks 60. This question paper contains 4 questions and 5 pages. Page 1 of 5

2 ANSWER ANY THREE QUESTIONS QUESTION 1: (20 MARKS) (a) What is an abstract data type? (b) Give two limitations of the array implementation of lists. (c) Give the major disadvantage of the dynamic implementation of lists. (d) Give two advantages of the dynamic implementation of lists. (e) Write a program that copies the content of a file into another file. (1 mark) (2 marks) (7 marks) QUESTION 2: (20 MARKS) (a) Give the two conditions required by a binary tree of depth d to be an almost complete binary tree. (3 marks) (b) Determine what the following recursive C function computes. Write an iterative function to accomplish the same purpose. int func(int n) if (n == 0) return(0); return(n + func(n-1)); (c) Write a recursive algorithm to search a sorted array a for an element x between a[low] and a[high]. (7 marks) (d) Use your algorithm from part (c) to search for 17 from a sorted array that contains the elements 1, 3, 4, 5, 17, 18, 31 and 33. Page 2 of 5

3 QUESTION 3: (20 MARKS) (a) Convert each of the following expressions to prefix and postfix. (i) (A+B)*(C+D) (ii) A-B/(C*D^E) (^ denotes exponentiation) (b) The following algorithm converts an infix expression into its postfix representation. We have assumed that the infix expressions contain only the operators +, -, * and /. The expressions do not contain parentheses. Examples of valid expressions are A+B*C and A/B+C/D-E. opstk = the empty stack; while (not end of input) symb = next input character; if (symb is an operand) add symb to the postfix string else while(!empty(opstk) && prcd(stacktop(opstk),symb)) topsymb = pop(opstk); add topsymb to the postfix string; push(opstk,symb); while(!empty(opstk)) topsymb = pop(opstk); add topsymb to the postfix string; (i) Write the function empty in C. The function empty must return TRUE if the stack is empty and FALSE if the stack is not empty. (ii) Write the function pop in C. The function must perform the following three actions: 1. If the stack is empty, print a warning message and halt execution. 2. Remove the top element from the stack. 3. Return the top element of the stack to the calling function. (iii) Write the function prcd(op1,op2) in C, where op1 and op2 are characters representing operators. The function prcd(op1,op2) must return TRUE if op1 has precedence over op2 when op1 appears to the left of op2 in an infix expression. The function prcd(op1,op2) returns FALSE otherwise. Page 3 of 5

4 QUESTION 4: (20 MARKS) (a) Give the representation of a queue as an abstract data type. (b) What is a priority queue? Give two types of priority queues. (c) The following program does the following: 1. Create a queue, q, consisting of 1 (front), 2, 3, 4 and 5 (rear). 2. Display the contents of q. 3. Remove an item from q and display the content of q. #include<stdio.h> #include<stdlib.h> #define MAXQUEUE 6 #define TRUE 1 #define FALSE 0 struct queue int items[maxqueue]; int front, rear; ; void initialize(); int empty(); void insert(); int rem(); void output(); int n; void main() struct queue q; int i,e; initialize(&q); printf("enter the number of elements: "); scanf("%d",&n); Page 4 of 5

5 If (n<maxqueue) for(i=0;i<n;i++) printf("enter an element: "); scanf("%d",&e); insert(&q,e); else printf("number of elements must be less than MAXQUEUE.\n"); return; printf("\ncontent of the Queue from Front to Rear: "); output(&q); rem(&q); printf("\ncontent of the Queue from Front to Rear: "); output(&q); Write the functions initialize, empty, insert and rem in C. (11 marks) ***END OF QUESTION PAPER*** Page 5 of 5