CSC141, Computer Science I, Instructor: Dr. Zhen Jiang, Test 2

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1 CSC141, Computer Science I, Instructor: Dr. Zhen Jiang, Test 2 Name(print) Student Number Page Points Score Total 100 1

2 Part 1 (56 pts): Select the correct printout result of the following program (only one needed) 1) The following program will print out ( A ) x=50; if (x<60) 2) The following program will print out ( B ) x=60; if (x<60) 3) The following program will print out ( B ) x=70; if (x<60) 4) The following program will print out ( C ) x=80; if (x<60) 2

3 5) The following program will print out ( C ) x=90; if (x<60) 6) The following program will print out ( C ) x=50; 7) The following program will print out ( C ) x=60; 8) The following program will print out ( D ) x=70; 3

4 9) The following program will print out ( A ) x=80; 10) The following program will print out ( A ) x=90; 11) The following program will print out ( D ) x=50; 12) The following program will print out ( D ) x=60; 4

5 13) The following program will print out ( D ) x=70; 14) The following program will print out ( D ) x=80; 15) The following program will print out ( D ) x=90; 5

6 16) The following program will print out ( D ) x = 0; while (x<3) { y=y+1; ; ( 17) The following program will print out ( B ) x = 0; while (x<3) y=y+1; ( 18) The following program will print out ( G ) x = 0; while (x<3) { y=y+x+1; ; 19) The following program will print out ( D ) x = 2; while (x<3) { y=y+x+1; ; 6

7 20) The following program will print out ( E ) x = 2; y = 1; while (x<3) { y=y+x+1; ; 21) The following program will print out ( C ) x = 0; while (x< 3) { x=x+2; ; 22) The following program will print out ( G ) x = 0; while (x< 3) { x=x+2; ; 23) The following program will print out ( G ) x = 0; do { while (x < 3); 7

8 24) The following program will print out ( D ) x = 3; do { while (x < 3); 25) The following program will print out ( A ) for (y=0, x = 3; x < 3; x ++) 26) The following program will print out ( C ) for (y=0, x = 0; x < 3; x ++) { 27) The following program will print out ( D ) for (y=0, x = 0; x < 3; ) { System.out.println (y) 28) The following program will print out ( E ) for (y=0, x = 0; x ++< 3; ) { 8

9 Part 2 (44 pts): Complete the following loop program. For each problem below, write some Java code to solve it. You do not need to define a class or the main method, or import any classes. For this question, you should assume that all necessary classes (e.g., Scanner, Arrays) have been imported. Furthermore, assume that the following line precedes every question below, for you to use if you want: Scanner kb = new Scanner(System.in); a. Write code that reads in an integer N, and displays all the products of 7, from N x 7 down to 1 x 7. For instance, if the user enters 4, the program should display: 4x7 = 28 3x7 = 21 2x7 = 14 1x7 = 7 Scanner kb = new Scanner(System.in); int n = kb.nextint(); for(int i = 0; i<n; i++){ System.out.println((n-i)+"x7="+(n-i)*7); 9

10 b. Write a program that reads in an integer n from the keyboard, and displays whether n is a "perfect number" or not. A number is "perfect" if it is equal to the sum of all of its factors (not including itself as a factor, but including 1 as a factor). 6 is the first perfect number, because its factors are 1, 2, and 3, and = 6. Scanner kb = new Scanner(System.in); int n = kb.nextint(); int total = 0; for (int i = 1; i<n; i++){ if(n%i==0) total+=i; System.out.println(n==total); 10

11 c. Develop a program that calculates the average salary of a person who earn over a period of time if his or her salary is one penny first day, two pennies the second day, four pennies the third day, and continues to double each day. The program should ask the user to enter the number of days worked and this program only accepts the number more than 1. Then, the program shows the result in the currency format, such as $0.03 for 4 days, and $0.06 for 5 days. Scanner kb = new Scanner(System.in); int n = kb.nextint(); while(n<=1){ System.out.println("Input a number until >1."); n=kb.nextint(); int salary = 1; int total = salary; for(int i = 0; i<n-1; i++){ salary *=2; total += salary; double average = total/n; average/=100; System.out.println("$"+average); 11

12 d. Develop a program that reads in a number n from the user (i.e., keyboard), and displays a figure with 2n columns and 2n rows of "*" and characters. For instance, if the user enters a 5 for n, your program should display the following shape: ********** **** **** *** *** ** ** * * * * ** ** *** *** **** **** ********** Scanner kb = new Scanner(System.in); int n = kb.nextint(); for(int i = 0; i< n; i++){ for(int j = 0; j < n - i; j++) System.out.print("*"); for(int j = 0; j< 2*i; j++) System.out.print(" "); for(int j = 0; j< n -i;j++) System.out.print("*"); System.out.println(); for(int i = 1; i<=n; i++){ for(int j = 0; j < i; j++) System.out.print("*"); for(int j = 0; j< 2*n-2*i; j++) System.out.print(" "); for(int j = 0; j< i;j++) System.out.print("*"); System.out.println(); 12

CIS 1068 Program Design and Abstraction Spring2016 Midterm Exam 1. Name SOLUTION

CIS 1068 Program Design and Abstraction Spring2016 Midterm Exam 1 Name SOLUTION Page Points Score 2 15 3 8 4 18 5 10 6 7 7 7 8 14 9 11 10 10 Total 100 1 P age 1. Program Traces (41 points, 50 minutes)