Solutions to Simple Arithmetic exercises

1. Correct values of i:

   1. i = 2
   2. i = 2
   3. i = 2

2. Because the '/' operator performs integer division when operating on integer variables; any remainder after the division is discarded. Thus, since 12 = (2 * 5) + 2, the remainder of 2 is ignored and the answer is 2.

3. Correct values of i:

   1. i = 1
   2. i = 56
   3. i = -70

4. Because the additional parentheses in 3.3 change the order of evaluation. In 3.2, the calculation is: 11 times 7 = 77; 21 minus 42 = -21; -21 plus 77 = 56. In 3.3 the calculation is: 21 minus 42 = -21; -21 plus 11 = -10; -10 times 7 = -70.

5. The largest and smallest int values are 2147483647 and -2147483648 respectively. Any program that prints these numbers is correct.

6. The largest and smallest long values are 9223372036854775807 and -9223372036854775808 respectively. The corresponding values for a short are 32767 and -32768. Any programs that print these numbers are correct.

7. One possible solution:

   1  import java.io.*;
   2
   3  class Prog24 {
   4    // Read two integers and do some arithmetic on them
   5
   6    public static void main(String[] args) throws NumberFormatException, IOException {
   7      int i, j;
   8      String num;
   9      BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
   10
   11     System.out.print("Please enter an integer: ");
   12     num = in.readLine();
   13     i = Integer.parseInt(num);
   14     System.out.print("Please enter another integer: ");
   15     num = in.readLine();
   16     j = Integer.parseInt(num);
   17     System.out.println("i + j = " + (i + j));
   18     System.out.println("i - j = " + (i - j));
   19     System.out.println("i * j = " + (i * j));
   20     System.out.println("i / j = " + (i / j));
   21     System.out.println("i % j = " + (i % j));
   22   }
   23 }
   	

8. One possible solution:

   1  import java.io.*;
   2
   3  class Prog24 {
   4    // Read two long integers and do some arithmetic on them
   5
   6    public static void main(String[] args) throws NumberFormatException, IOException {
   7      long i, j;
   8      String num;
   9      BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
   10
   11     System.out.print("Please enter a long integer: ");
   12     num = in.readLine();
   13     i = Long.parseLong(num);
   14     System.out.print("Please enter another long integer: ");
   15     num = in.readLine();
   16     j = Long.parseLong(num);
   17     System.out.println("i + j = " + (i + j));
   18     System.out.println("i - j = " + (i - j));
   19     System.out.println("i * j = " + (i * j));
   20     System.out.println("i / j = " + (i / j));
   21     System.out.println("i % j = " + (i % j));
   22   }
   23 }