Questions and Exercises: Operators

Questions

1. Consider the following code snippet.

   arrayOfInts[j] > arrayOfInts[j+1]
   

   Which operators does the code contain?

2. Consider the following code snippet.

   int i = 10;
   int n = i++%5;
   

   1. What are the values of i and n after the code is executed?

   2. What are the final values of i and n if instead of using the postfix increment operator (i++), you use the prefix version (++i))?

3. To invert the value of a boolean, which operator would you use?

4. Which operator is used to compare two values, = or == ?

5. Explain the following code sample: result = someCondition ? value1 : value2;

Exercises

1. Change the following program to use compound assignments:

   class ArithmeticDemo {
   
        public static void main (String[] args){
             
             int result = 1 + 2; // result is now 3
             System.out.println(result);
   
             result = result - 1; // result is now 2
             System.out.println(result);
   
             result = result * 2; // result is now 4
             System.out.println(result);
   
             result = result / 2; // result is now 2
             System.out.println(result);
   
             result = result + 8; // result is now 10
             result = result % 7; // result is now 3
             System.out.println(result);
   
        }
   }
   
   

2. In the following program, explain why the value "6" is printed twice in a row:

   class PrePostDemo {
        public static void main(String[] args){
             int i = 3;
   	  i++;
   	  System.out.println(i);	// "4"
   	  ++i;			   
   	  System.out.println(i);	// "5"
   	  System.out.println(++i);	// "6"
   	  System.out.println(i++);	// "6"
   	  System.out.println(i);	// "7"
        }
   }