Solutions to the 'Making Decisions' Exercises

1. The program will print unknown transaction type! no matter what input it is given. This is because == does not compare the individual characters in each string, but rather checks whether the two are the 'same' string.

2. 1  import java.io.*;
   2  
   3  class Ex42 {
   4  
   5    public static void main(String args[]) throws IOException {
   6  
   7      BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
   8      String line1, line2;
   9  
   10     System.out.print("Enter some text: ");
   11     line1 = in.readLine();
   12     System.out.print("Enter some more: ");
   13     line2 = in.readLine();
   14 
   15     if (line1.equals(line2)) {
   16       System.out.println("Snap!");
   17     }
   18   }
   19 }
   	

3. 1  import java.io.*;
   2  
   3  class Ex43 {
   4  
   5    public static void main(String args[]) throws IOException {
   6  
   7      BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
   8      int num1, num2;
   9  
   10     System.out.print("Enter a number: ");
   11     num1 = Integer.parseInt(in.readLine());
   12     System.out.print("Enter another: ");
   13     num2 = Integer.parseInt(in.readLine());
   14 
   15     if (num1 == num2) {
   16       System.out.println("Equal!");
   17     }
   18     else if (num1 > num2) {
   19       System.out.println("Greater!");
   20     }
   21     else {
   22       System.out.println("Less!");
   23     }
   24   }
   25 }
   	

4. For x = 27 and y = 42, the code will print less than. For x = 12 and y = 9 it will print close, but greater than.

5. switch (i) {
    case 1:
    case 2:
    case 3:
    case 4:
    case 5:
     System.out.println("Group A");
     break;
    case 6:
    case 7:
    case 8:
    case 9:
    case 10:
     System.out.println("Group B");
     break;
    case 11:
    case 12:
    case 13:
    case 14:
    case 15:
     System.out.println("Group C");
     break;
    default:
     System.out.println("Group D");
   }
   	

6. if ((c == 'a') || (c == 'A')) {
     System.out.println("Option A selected");
   }
   else if ((c == 'b') || (c == 'B')) {
     System.out.println("Option B selected");
   }
   else if ((c == 'c') || (c == 'C')) {
     System.out.println("Option C selected");
   }
   else {
     System.out.println("Unknown option selected");
   }
   	

7. 1  import java.io.*;
   2  
   3  class Ex47 {
   4  
   5    public static void main(String[] args) throws IOException {
   6  
   7      System.out.print("Enter a character: ");
   8      char c = (char)System.in.read();
   9  
   10     if (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u') {
   11       System.out.println("Vowel");
   12     }
   13     else if (c == 'b' || c == 'c' || c == 'd' || c == 'f' || c == 'g' ||
   14              c == 'h' || c == 'j' || c == 'k' || c == 'l' || c == 'm' ||
   15              c == 'n' || c == 'p' || c == 'q' || c == 'r' || c == 's' ||
   16              c == 't' || c == 'v' || c == 'w' || c == 'x' || c == 'y' ||
   17              c == 'z') {
   18       System.out.println("Consonant");
   19     }
   20     else if (c == '0' || c == '1' || c == '2' || c == '3' || c == '4' ||
   21              c == '5' || c == '6' || c == '7' || c == '8' || c == '9') {
   22       System.out.println("Digit");
   23     }
   24     else {
   25       System.out.println("Other character");
   26     }
   27   }
   28 }
   	

8. 1  import java.io.*;
   2  
   3  class Ex48 {
   4  
   5    public static void main(String[] args) throws IOException {
   6  
   7      System.out.print("Enter a character: ");
   8      char c = (char)System.in.read();
   9  
   10     switch (c) {
   11      case 'a':
   12      case 'e':
   13      case 'i':
   14      case 'o':
   15      case 'u':
   16       System.out.println("Vowel");
   17       break;
   18      case 'b':
   19      case 'c':
   20      case 'd':
   21      case 'f':
   22      case 'g':
   23      case 'h':
   24      case 'j':
   25      case 'k':
   26      case 'l':
   27      case 'm':
   28      case 'n':
   29      case 'p':
   30      case 'q':
   31      case 'r':
   32      case 's':
   33      case 't':
   34      case 'v':
   35      case 'w':
   36      case 'x':
   37      case 'y':
   28      case 'z':
   39       System.out.println("Consonant");
   40       break;
   41      case '0':
   42      case '1':
   43      case '2':
   44      case '3':
   45      case '4':
   46      case '5':
   47      case '6':
   48      case '7':
   49      case '8':
   50      case '9':
   51       System.out.println("Digit");
   52       break;
   53      default:
   54       System.out.println("Other character");
   55     }
   56   }
   57 }