CS Computers & Programming I Review_01 Dr. H. Assadipour

Size: px

Start display at page:

Download "CS Computers & Programming I Review_01 Dr. H. Assadipour"

Janice Kelley
6 years ago
Views:

1 CS Computers & Programming I Review_01 Dr. H. Assadipour 1. What is the output of this program? public class Q_01 public static void main(string [] args) int x=8; int y=5; double z=12; System.out.println(y/x); System.out.println(z/x); System.out.println(y%x); x=y; y=x; System.out.println(x); System.out.println(y); Ï 0 ÏÏ Ï 1.5 ÏÏ Ï5 ÏÏ Ï5 Ï Ï 5 2. What is the output of this program? public class Q_02 public static void main(string [] args) for(int i=0; i<3; i++) System.out.println(i); for(int j=i; j<=3; j++) System.out.println(j); 0 ÏÏ 0 ÏÏ 1 ÏÏ 2 ÏÏ 1 ÏÏ 1 ÏÏ 2 ÏÏ 2 ÏÏ 2 3. What is the output of this program? public class Q_03 public static void main(string [] args) for(int i=1; i<10; i++) if(i>=6) System.out.println(i); else if(i>=4) System.out.println(3); else System.out.println(0); Ï 0 ÏÏ 0 ÏÏ 0 ÏÏ 6 ÏÏ 7 ÏÏ 8 ÏÏ 9 1

2 4. What is the output of this program? public class Q_04 public static void main(string [] args) int n=1; while(n<512) n=2*n; System.out.println(n); 2 ÏÏ 4 ÏÏ 8 ÏÏ 16 2 ÏÏ 64 ÏÏ 128 ÏÏ 256 ÏÏ What is the output of this program? public class Q_05 public static void main(string [] args) int[] a=1,2,6,3,2; for(int i=0; i<a.length; i++) System.out.println(a[i]); for(int i=0; i<a.length; i++) a[i]=a[i]-i; for(int i=0; i<a.length; i++) System.out.println(a[i]); Ï1 ÏÏ 2 ÏÏ 6 ÏÏ 2 ÏÏ 1 ÏÏ 1 ÏÏ 4 ÏÏ 0 ÏÏ Consider the array declaration double[] x=new double[5]; (a) What is the type of x[4]? (b) How many elements does x have? (c) What is the smallest index i such that x[i] is valid? (d) What is the value of x.length? (e) What is the largest index i such that x[i] is valid? (a) double (b) five (c) zero (d) five (e) four 2

3 7. Suppose you are designing a class. (a) What would you use to represent the state of an object? (b) What are accessor methods used for? (c) What are constructors used for? (d) Why is it useful to implement tostring()? (e) Why is it useful to make instance variables private? (a) data (b) to read the data of the object (c) to instantiate an object (d) display all state information (e) encapsulation 8. What is the output of this program? public class Q_08 int x=0; for(int i=1; i<=10; i++) x=x+i; System.out.println(x); System.out.println(x); Ï What is the output of this program? public class Q_09 int sum=0; for(int i=1; i<=5; i++) sum += i*i; System.out.println(sum); Ï 1 ÏÏ 5 ÏÏ 14 0 ÏÏ 55 3

4 10. What is the output of this program? public class Q_10 int sum=0; int[] a =1, 2, 3, 4, 5; for(int i=1; i<=5; i++) sum += i; System.out.println(sum); 1 ÏÏ 6 ÏÏ 10 ÏÏ Write a program that reads a single integer n, and then prints the sum n 3. import java.util.scanner; public class Q_11 int n, sum=0; Scanner input = new Scanner(System.in); System.out.print("Enter n: "); n = input.nextint(); for (int i = 1; i<=n; i++) sum += Math.pow(i, 3); System.out.println("The sum of all cubes = " + sum); 12. A class declares the instance variable private int[] a; Implement the static method sum( ) that returns the sum of the elements of a. import java.util.scanner; public class Q_12 int [] Ray = 1, 2, 3, 4, 5; System.out.println("The sum of elements: "+ sum(ray, Ray.length)); public static int sum(int[] x, int y) int total = 0; for(int i =0; i<y; i++) total += x[i]; return total; 4

5 13. Write a program to print the odd numbers from 1 to 100 in increasing order. public class Q_13 for(int i = 1; i<100; i += 2) System.out.println(i); 14. Write a program to read integers until a zero is input. The program then prints the sum of the integers that were input and the number of negative integers that were input. import java.util.scanner; public class Q_14 int n, neg_count = 0, sum = 0; Scanner input = new Scanner(System.in); System.out.println("Enter n: "); n = input.nextint(); while(n!=0) n = input.nextint(); if (n <0) neg_count++; sum +=n; System.out.println("#of negatives: " + neg_count + "\t" +"Total = " + sum); 5

6 15. Write a program that reads an array of integers, representing grades from a data file and displays the max, min, average, and the standard deviation of the elements of the array. You must include two static methods one named avg (for the mean) and one named std_dev (for standard deviation). Data File: Here is a sample output with the expected results Sample Run: ----jgrasp exec: java PP_7_ The max = 95 The min = 48 The avg = The sd = jgrasp: operation complete 6

7 import java.util.scanner; import java.io.*; public class Q_15 throws IOException Scanner filescan = new Scanner(new File("grade.dat")); int [] grade = new int[20]; for (int i = 0; i<20; i++) grade[i] = filescan.nextint(); for (int i = 0; i<20; i++) System.out.print(grade[i] + "\t"); System.out.println(); System.out.println("The max = " + Max(grade, 20)); System.out.println("The min = " + Min(grade, 20)); System.out.println("The avg = " + Avg(grade, 20)); System.out.println("The sd = " + std_dev(grade, 20,Avg(grade, 20))); public static int Max(int [] x, int y) int maximum = x[0]; for(int i = 1; i<20; i++) if(x[i]>maximum) maximum = x[i]; return maximum; public static int Min(int [] x, int y) int minimum = x[0]; for(int i = 1; i<20; i++) if(x[i]<minimum) minimum = x[i]; return minimum; public static double Avg(int [] x, int y) int sum = 0; for(int i = 0; i<20; i++) sum += x[i]; return sum/20.; public static double std_dev(int [] x, int y, double average) int sum = 0; for(int i = 0; i<20; i++) sum += Math.pow((x[i]-average),2); return Math.sqrt(sum/19.); 7

8 16. Write a static method: public static int f(int n), that returns 0 if n is even, and if n is odd, returns 1 or -1 according as n is greater than or less than 0. import java.util.scanner; public class Q_16 public static void main(string args[]) int n; Scanner input = new Scanner(System.in); System.out.print("Please enetr n: "); n = input.nextint(); System.out.println(f(n)); public static int f(int a) if (a%2 == 0) return 0; else if(a > 0) return 1; else return -1; 8

9 17. A class declares instance variables Write: private int number; private String name; (a) accessor methods getnumber() and getname() for the instance variables. (b) a mutator method add(int m) that increments number by m. public class Q_17_Driver public static void main(string args[]) int m = 5; Q_17 obj_01 = new Q_17(5, "James"); System.out.println(obj_01.getNumber()); System.out.println(obj_01.getName()); obj_01.add(m); System.out.println(obj_01.getNumber()); System.out.println(obj_01.getName()); public class Q_17 private int number; private String Name; public Q_17 (int n, String N) number = n; Name = N; public int getnumber () return number; public String getname () return Name; public void add (int n) number += n; 9

10 18. Write a program that declares a 2-D array, T[i][j], representing high and low temperatures for the 12 months of the year. Your program reads the following data from a data file (temp.txt) and stores these values in the array just declared. Ï Ï Your program will contain methods that calculate: ÏThe max of high temp = 98 ÏThe min of low temp = 2 ÏThe max of low temp = 75 ÏThe min of high temp = 30 ÏThe high avg = 60.5 ÏThe low avg = ÏThe high std = ÏThe low std = import java.util.scanner; import java.io.*; import java.text.decimalformat; public class Q_18 public static void main(string[]args) throws IOException Scanner filescan= new Scanner (new File ("temp.txt")); int[][] temp = new int[2][12]; for (int i=0; i<2; i++) temp[i][j]=filescan.nextint(); for (int i=0; i<2; i++) System.out.print("\t" + temp[i][j] + "\t"); System.out.println(); DecimalFormat fmt= new DecimalFormat ("0.##"); System.out.println("The max of high temp =" + maximum(temp,12)); System.out.println("The min of low temp =" + minimum(temp,12)); System.out.println("The max of low temp =" + l_maximum(temp,12)); System.out.println("The min of high temp =" + h_minimum(temp,12)); System.out.println("The high avg =" + fmt.format (h_avg(temp,12))); System.out.println("The low avg =" + fmt.format (l_avg(temp,12))); System.out.println("The high std =" + fmt.format (sd(temp,12,h_avg(temp,12)))); System.out.println("The low std =" + fmt.format (lsd(temp,12,l_avg(temp,12)))); public static int maximum (int[][] x,int y) 10

11 int max=x[0][0]; for(int i=0; i<1; i++) if(x[i][j]>max) max=x[i][j]; return max; public static int minimum (int[][] x,int y) int min=x[0][0]; for(int i=1; i<2; i++) if(x[i][j]<min) min=x[i][j]; return min; public static double h_avg (int[][] x,double y) double sum=0; for(int i=0; i<1; i++) sum += x[i][j]; return sum/12; public static double l_avg (int[][] x,int y) double sum=0; for(int i=1; i<2; i++) sum += x[i][j]; return sum/12; 11

12 public static double sd (int[][] x, int y,double average) int sum = 0; for(int i=0; i<1; i++) sum += Math.pow (x[i][j] - average, 2); return Math.sqrt (sum/(11.)); public static double lsd (int[][] x, int y,double average) int sum = 0; for(int i=1; i<2; i++) sum += Math.pow (x[i][j] - average, 2); return Math.sqrt (sum/(11.)); public static int l_maximum (int[][] x,int y) int max=x[0][0]; for(int i=1; i<2; i++) if(x[i][j]>max) max=x[i][j]; return max; public static int h_minimum (int[][] x,int y) int min=x[0][0]; for(int i=0; i<1; i++) if(x[i][j]<min) min=x[i][j]; return min; 12

COE 212 Engineering Programming. Welcome to the Final Exam Tuesday December 15, 2015

1 COE 212 Engineering Programming Welcome to the Final Exam Tuesday December 15, 2015 Instructors: Dr. Salim Haddad Dr. Bachir Habib Dr. Joe Tekli Dr. Wissam F. Fawaz Name: Student ID: Instructions: 1.