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"
 }
}